molecular order and mobility in polymer systems · 8th international symposium “molecular order...
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Molecular Order and Mobility
in Polymer Systems
Under the sponsorship of IUPAC
BOOK OF ABSTRACTS
St. Petersburg, June 2-6, 2014
8 International Symposium
УДК 539.2, 541, 542
ISBN
8th International Symposium “Molecular Order and Mobility in Polymer Systems”
BOOK OF ABSTRACTS. Saint-Petersburg, 2014. - рp.
INTERNATIONAL SCIENTIFIC ADVISORY BOARD
K. Binder, Germany T.M. Birshtein, RussiaA. Eisenberg, CanadaG. Fleer, NetherlandsYu.Ya. Gotlib, Russia A.R.Khokhlov, RussiaA.M. Muzafarov, RussiaE.F.Panarin, Russia M. Textor, Switzerland
PROGRAM COMMITTEE
T.M. Birshtein - ChairmanA.A. Darinskii - Vice-ChairmanO.V. BorisovG.K. ElyashevichA.P. Filippov I.M. Neelov E.F. Panarin T.E. Tennikova M.V. Uspenskaya V.E. Yudin A.V. Yakimansky
LOCAL ORGANIZING COMMITTEE
V.D. Pautov - ChairmanT.V. Filippova - CoordinatorA.G. Ivanov M.L. Levit A.A. Polotsky R.Yu. Smyslov E.B. Tarabukina
SYMPOSIUM TECHNICAL SECRETARIATEMONOMAX LTD
© Institution of Russian Academy of Sciences Institute of Macromolecular Compounds RAS
UNDER THE SPONSORSHIP OF IUPAC
8th International Symposium
Molecular Order and Mobility
in Polymer Systems
St. Petersburg, June 2-6, 2014
BOOK OF ABSTRACTS
Organized by:
DEPARTMENT OF CHEMISTRY AND MATERIAL SCIENCE OF RUSSIAN ACADEMY OF SCIENCES POLYMER COUNCIL OF RUSSIAN ACADEMY OF SCIENCES
INSTITUTE OF MACROMOLECULAR COMPOUNDS RAS ST. PETERSBURG NATIONAL RESEARCH UNIVERSITY OF INFORMATION TECHNOLOGIES, MECHANICS AND OPTICS (ITMO UNIVERSITY)
Supported and sponsored by:
RUSSIAN FOUNDATION FOR BASIC RESEARCH INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY
L'OREAL AGILENT TECHNOLOGIES SIBUR HOLDING
XENOCS
ST. PETERSBURG RESEARCH CENTER OF RUSSIAN ACADEMY OF SCIENCES
Promoted through: Professional Congress Organizer Monomax Congresses & Incentives, St. Petersburg, Russia
CONTENTS Plenary lectures ........................................................................................................L-001 – L-013 Oral presentations....................................................................................................O-001 – O-081 Poster presentations.................................................................................................P-001 – P-193 Index
PLENARY LECTURES
L-01 PHASE TRANSITION IN THIN FILMS OF THERMOSENSITIVE POLYMERS: A STUDY BY NEUTRON REFLECTIVITY
A. Steitz1, J. Dzubiella2, M. Ballauff2
1 - Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany 2 - Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany;
Department of Physics, Humboldt-University Berlin, Newtonstr. 15, 12489 Berlin, Germany [email protected]
We present our recent work on phase transition in film of thermosensitive polymers attached to a planr surface. In particular, we study the response of stimuli-responsive polymer brushes to moderately elevated pressure by neutron reflectivity. The results are compared to a thermodynamically consistent density functional theory in which pressure effects are included by a hydrophobic cavity model. Evidence is provided that temperature and pressure effects on the brush spatial structure are perfectly antagonistic. A ~100 bar/K cancellation effect is found, which we argue is a universal feature for hydrophobically associating polymers and serves for experimental guidance and fine-control of polymer film structure.
L-02 PROPAGATING POLYMER FRONTS IN CONFINED POLYMER SYSTEMS
J. Genzer
NC State University [email protected]
Bulk free radical polymerization reactions lead to highly polydisperse polymers (polydispersity index, PDI >> 1.5). In the past, researchers have shown that polymerization in porous microreactors can lower polydispersity (PDI 1.5~1.7) by promoting gelation. We employ free-radical thermal frontal polymerization reaction of acrylamide (AAm) in dimethyl sulfoxide (DMSO) in highly confined reactors (height < 1mm) to produce high molecular weight (~300 kDa) PAAm of relatively low PDI (~1.2). In frontal polymerization systems, a localized reaction zone propagates in space along the direction of heat transfer, sustained by the interplay of heat diffusion and Arrhenius reaction kinetics. The directional heat transfer assists in maintaining the uniformity of the front temperature. While convection improves thermal transport, it causes inhomogeneity in the propagating front in horizontal reactors. In highly confined systems, convection is heavily suppressed, as manifested by the “flattening” of the reaction front and the absence of “fingering”. Gelation lowers termination rate and increases the life time of the active reaction centers. Elimination of convection in confined geometries coupled with directional heat transfer and gelation results in polymers with high molecular weights and low PDIs.
L-03 A VERY HIGH CAPACITY POLYMERIC MICELLE DRUG DELIVERY SYSTEM
A. Kabanov1, R. Jordan2, R. Luxenhofer3
1 - Center for Nanotechnology in Drug Delivery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7362, USA
2 - Technische Universitat Dresden, Professur fur Makromolekulare Chemie, Department Chemie, Mommsenstr. 4, 01069 Dresden, Germany
3 - Functional Polymer Materials, Chair of Chemical Technology of Materials Synthesis, University Wurzburg, Rontgenring 11, 97070 Wurzburg, Germany
Polymeric micelles proposed as carriers for drug delivery in the end of 80-ies by Kabanov’s and Kataoka’s groups have now reached a clinical stage with one polymer micelle product approved and number of others undergoing clinical trials. One “value proposition” of polymeric micelles is their ability to incorporate water-insoluble drugs. However, only few drugs and polymeric micelle systems displayed loading capacities of even 10-20% (wt. drug / wt. drug and polymer) with most others having lower capacities. We discovered that polymeric micelles of poly(2-methyl-2-oxazoline) (PMeOx) and poly(2-butyl-2-oxazoline) (PBuOx) triblock copolymer PMeOx-PBuOx-PMeOx have an unprecedented high loading capacity of nearly 50% for paclitaxel (PTX), docetaxel (DTX) as well as other drugs and multi-drug combinations. Such loading capacity is due to a unique multi-domain structure of the PBuOx hydrophobic core, which can accommodate both hydrophobic and polar groups of many drug molecules. As a result the amount of the polymer used is greatly decreased (e.g. nearly 50 times compared to Chremophor EL in Taxol) and the maximal tolerated dose (MTD) increased (e.g. in a mouse 7 times vs. Taxol). Due to greater exposure at the increased and safe dose the drug more efficiently kills the tumor cells resulting in more efficient therapy. Multiple drugs and drug combinations can be solubilized providing for a versatile drug delivery platform for 1) rescuing “undruggable” molecules; 2) reformulating existing drugs; and 3) creating multi-drug combinations that affect synergistic pathways and more efficiently cure the disease. Acknowledgments: Support from Cancer Nanotechnology Platform Partnership grant (U01 CA116591).
L-04 SHAPE MEMORY BEHAVIOR OF POLYMERS, COPOLYMERS AND NANOCOMPOSITES
L. Peponi1, I. Navarro Baena2, J.M. Kenny3
1 - Institute of Polymer Science and Technology (ICTP-CSIC), Madrid, Spain 2 - University of Perugia, Terni, Italy
3 - Materials Science and Technology Centre, University of Perugia, Terni, Italy [email protected]
The research reported here is focused on the design of new polymeric materials based on biodegradable and biocompatible polymers, PCL and PLA, in order to obtain shape memory materials. To accomplish this goal, two strategies were planned: the synthesis of poly(ester-urethane)s with block copolymer structure and the processing of polymer blends. A specific study on the relationship between the thermal behavior and the chemical structure of the materials developed is reported allowing a better understanding for designing specific polymeric structures able to show shape memory at desired transition temperatures. Furthermore, in order to increase the mechanical behavior of the neat matrices, different kinds of bionanocomposites were also studied with particular attention to nano hydroxyapatite and cellulose nanocrystals. Both nanofillers are biocompatible, thus representing a good solution to improve the mechanical properties of PLA and PCL matrices without affecting the character bio of the polymer composites. In this way the elastic modulus of the bionanocomposites is increased as well as the shape memory parameters such as the stress recovery and the shape fixity ratios. In fact, this work reports shape memory tests on the neat materials as well as on the bionanocomposites, quantifying this unique effect and studying the influence of the tests conditions on the shape memory parameters. The bio-nature of the materials is also analyzed by degradation studies of the different materials, neat and reinforced, in compost as well as in vitro. So, this report provides a comprehensive scientific approach to the shape memory behavior of PCL-PLA based systems relevant for future applications in advanced technological fields.
L-05 SURFACE FORCES WITH CHARGED MACROMOLECULES: DISENTANGLING STERIC FROM ELECTROSTATIC EFFECTS
J. Klein
Weizmann Institute of Science, Rehovot 76100, Israel [email protected]
Interactions between macromolecular surface phases may arise either from steric forces due to excluded volume effects, or from long-ranged electrostatic double-layer interactions when the surface assemblies are charged, or a combination of the two. Studies, including AFM or surface force balance (SFB), of the equilibrium forces between surface-attached species such as liposomes or polyelectrolyte brushes, both of which may have residual charges, cannot discriminate between these effects. For the first time we have now simultaneously measured both equilibrium and dynamic forces between charged surface assemblies, including liposomes and charged brushes, and in this way clearly deconvoluted the steric/hydrodynamic from the electrostatic interactions. Our results reveal an unexpected coupling between the two. I particularly thank my co-workers Reut Peretz and Gilad Silbert, together with Nir Kampf, who carried out the studies described here.
L-06 LARGE-SCALE ATOMISTIC AND QUANTUM-MECHANICAL SIMULATIONS OF A NAFION MEMBRANE: MORPHOLOGY, PROTON
SOLVATION AND CHARGE TRANSPORT
A.R. Khokhlov1, P.V. Komarov2, P.G. Khalatur3 1 - Physics Department, Moscow State University, Moscow, Russia 2 - Institute of Organoelement Compounds, RAS, Moscow, Russia
3 - Department of Theoretical Physics, Tver State University, Tver, Russia [email protected]
Atomistic and first-principles molecular dynamics simulations are employed to investigate the structure formation in a hydrated Nafion membrane and the solvation and transport of protons in the water channel of the membrane. For the water/Nafion systems containing more than 4 million atoms, it is found that the observed microphase-segregated morphology can be classified as bicontinuous: both majority (hydrophobic) and minority (hydrophilic) subphases are 3D continuous and organized in an irregular ordered pattern, which is largely similar to that known for a bicontinuous double-diamond structure. The characteristic size of the connected hydrophilic channels is about 25–50 Å, depending on the water content. A thermodynamic decomposition of the potential of mean force and the calculated spectral densities of the hindered translational motions of cations reveal that ion association observed with decreasing temperature is largely an entropic effect related to the loss of low-frequency modes. Based on the results from the atomistic simulation of the morphology of Nafion, we developed a realistic model of ion-conducting hydrophilic channel within the Nafion membrane and studied it with quantum molecular dynamics. The extensive 120 ps-long density functional theory (DFT)-based simulations of charge migration in the 1200-atom model of the nanochannel consisting of Nafion chains and water molecules allowed us to observe the bimodality of the van Hove autocorrelation function, which provides the direct evidence of the Grotthuss bond-exchange (hopping) mechanism as a significant contributor to the proton conductivity.
L-07 POLYMER BRUSHES IN POOR SOLVENT: AN SELF-CONSISTENT FIELD ANALYSIS
F.A.M. Leermakers
Laboratory of Physical Chemistry and Colloid Science [email protected]
When linear chains are end-grafted onto a surface or are tethered onto an interface with a sufficiently high grafting density such that the chains laterally overlap, a so-called polymer brush is formed. We consider a planar neutral polymer brush in variable solvent conditions. According to classical brush theory, in good solvent conditions the brush is swollen. Upon a worsening of the solvent quality the brush gradually lowers its height until in very poor solvent condition a dense polymer layer remains. Hence the layer suffers no jump-like collapse. In this talk I elaborate on this somewhat puzzling result. Using a two-gradient version of the self-consistent field theory, it is now feasible to model laterally inhomogeneous brushes. With this approach we can prove that when the chains remain laterally mobile the collapse transition becomes jump-like. There exists a systematic analogy with the wetting of a liquid drop on a substrate, albeit that in the current situation the drop is flattened due to elastic stretching of the tethered chains. I will elaborate on the structure of such collapsed brush and here notice that the affinity of the brush for the interface is essential. I'll show that the classical brush theory can also be wrong when the chains have no lateral mobility. In a three-gradient self-consistent field model I show that in poor solvent conditions the laterally quenched brush produces a zoo of surface structures, wherefore the details of how the chains are grafted onto the substrate matter.
L-08 HIERARCHIAL AND RESPONSIVE STRUCTURAL ORGANIZATION FOR POLYMERS WITH ACTIVE PROPERTIES
M. Moeller
Institut fur Interaktive Materialien, Aachen, Germany [email protected]
L-09 PROCESS-DIRECTED ASSEMBLY OF BLOCK COPOLYMER MATERIALS
M. Mueller
Georg-August University, Institute for Theoretical Physics, Goettingen, Germany [email protected]
The free-energy landscape of self-assembling block copolymer systems is characterized by a multitude of metastable minima and concomitant protracted relaxation times of the morphology. Tailoring the kinetics of structure formation in block copolymers, we propose to reproducibly direct the self-assembly of block copolymers such that the system becomes trapped in a desired long-lived metastable morphology as illustrated in Fig. 1. To this end, it is necessary to (i) control the generation of well-defined, highly unstable states and (ii) design the unstable state such that the ensuing spontaneous kinetics of structure formation reaches the desired metastable morphology. This process-directed self-assembly1 provides an alternative to fine-tuning molecular architecture or blending for fabricating complex network structures. Comparing our particle-based simulation results to recently developed free-energy techniques, we critically assess their ability to predict spontaneous formation and highlight the importance of non-equilibrium molecular conformations in the starting state and the local conservation of density. 1 M. Müller and D.W. Sun, Phys. Rev. Lett. 111, 267801 (2013) Fig. 1: Process-directed assembly from a stable BCC morphology at fstart=0.15 to fend=0.5. Since the change of the thermodynamic state (quench) on the time scale 10-3s is fast compared to the structural relaxation, the system reaches the free-energy landscape (blue curve) of the new thermodynamic state, fend, in the BCC morphology (star) that is highly unstable. The spontaneous structure formation after this rapid quench becomes quickly trapped in the metastable I-WP network morphology on the time scale of 10s. Only after a much longer time, 103s, the thermo-dynamically stable LAM phase eventually nucleates via a thermal fluctuation, and the system reaches its new equilibrium, the LAM structure.
L-10 HOW TO USE POLYION-SURFACTANT ION "COMPLEX SALTS" TO BUILD STRUCTURED MATERIALS
L. Piculell
Physical Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden [email protected]
"Complex salts", consisting of polyions neutralized by surfactant counterions, are interesting materials, consisting of both ionic and non-polar entities. Owing to the strong tendency for self-assembly of the non-polar "tails" of the surfactant ions, it is often instructive to view a complex salt materials as consisting of surfactant (aggregates) with polymeric counterions. The latter perspective is particularly useful if the polyion is flexible, and if the complex salt is immersed in an aqueous environment. In a non-polar solvent, on the other hand, the complex salt dissolves essentially as individual bottle-brush polymer molecules, with bristles made up by surfactant ions, attached to the polyion main chain with ionic bonds. In the dry melt, finally, nano-segregated structures typically form, sometimes displaying a long-range crystalline order. Over the last decade, I have been involved in several mostly collaborative projects studying the structures formed by complex salts of poly(acrylate) or poly(methacrylate) polyions with alkyltrimethylammonium counterions in different contexts: As water-swelling, but water-insoluble structured materials, as oil-soluble reverse micelles or as amphiphilic blocks in block-copolymers with polystyrene. The studied complex salts are easily produced at varying ratios of surfactant ion to polymer repeat unit, simply by titrating of the poly(carboxylic acid) to different degrees with the hydroxide form of the cationic surfactant. The length and the number of long alkyl "tails" of the surfactat ion are other parameters that are readily varied. In this lecture, I will review some main trends emerging from the accumulated experimental observations, emphasizing the versatility and usefulness of complex salts as building blocks in hydrated, ordered bulk materials, visco-elastic oil-continuous solutions, water-responsive surface films, or structure-within-structure-forming block-copolymer melts. References: 1. Piculell, L. Understanding and exploiting the phase behavior of mixtures of oppositely charged polymers and surfactants in water. Langmuir, 2013, 29, 10313−10329. 2. Mehran Asad Ayoubi, Kaizheng zhu, Bo Nyström, Kristoffer Almdal, Ulf Olsson and Lennart Piculell, Micro- and nanophase separations in hierarchical self-assembly of strongly amphiphilic block copolymer-based ionic supramolecules. Soft Matter, 2013, 9, 1540-1555 The work was supported by the Swedish Research Council through an individual grant and a Linnaeus grant (239-2009-6794) to the Center of Excellence "Organizing Molecular Matter".
L-11 ARCHITECTURALLY-INDUCED DISENTANGLEMENT IN POLYMER MELTS AND DESIGN OF SUPER-SOFT AND SUPER-ELASTIC
NETWORKS
M. Rubinstein1, S.S. Sheiko1, J. Paturej1, W. Daniel1, L.-H. Cai2, K. Matyjaszewski3 1 - Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
2 - School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA 3 - Department of Chemistry, Carnegie Mellon University, Pittsburg, PA 15213, USA
Topological entanglements between polymer chains determine a lower limit of ~105 Pa for elastic modulus of conventional elastomers. Much softer materials are needed for a number of applications ranging from implants for reconstructive surgeries and tissue growth scaffolds to antibacterial and antifouling surfaces. The traditional way of reducing the modulus is to swell polymer networks with a solvent, which, however, can evaporate or diffuse out of these gels making them unacceptable for many applications. We propose several alternative routes for preparing super-soft dry networks with elastic moduli many orders of magnitude below that of conventional elastomers. These methods are based on (i) significant reduction of plateau modulus in molecular brushes with densely grafted side chains effectively acting as chemically attached solvent species and spacers between brush backbones and (ii) the absence of rubbery plateau in melts of non-concatenated entangled cyclic polymers. We predict elastic modulus (that can be much lower than kPa), maximum stretch ratio (that can be ~of the order of 100), and other mechanical properties of these super-soft and super-elastic networks and related unique properties of melts of bottle-brushes and rings in good agreement with experiments.
L-12 STRUCTURE-PROPERTY RELATIONSHIP OF HIGH-STRENGTH POLYMER GELS
M. Shibayama
The University of Tokyo, Institute for Solid State Physics, Kashiwa, Japan [email protected]
Gels are soft and fragile materials. Fragility in polymer gels has been a fatal problem for their various applications, such as actuators, replacement tissues in surgical operation, constructional materials, and so on. However, new types of high-performance gels, such as high-strength gels,[1-4] have been developed during the last decade, which have opened a door of potential application of gels to artificial muscle, tendon, gas-separation membrane, and others. In order to realize it, understanding of the structure-property relationship of these gels is inevitable. In this paper, recent progress in the understanding the structure–mechanical property relationship of high-strength gels made of multi-arm polyethylene glycol (PEG) is reviewed with a scope of future directions of polymer gel sciences.[5] Emphases are placed on tetra-arm PEG gels (Tetra-PEG) hydrogels[6] and ion gels[7] made via cross-end-coupling of four-arm PEG prepolymers having complementary functional groups[4]. Fine tunings of the molecular weight, prepolymer concentration, and the rate of coupling reaction allowed us to fabricate well-controlled polymer networks free from defects, entanglements and inhomogeneities. The unique structure and dynamics were confirmed by a series of structural investigations with small-angle neutron scattering (SANS) and static light scattering (SLS), and with dynamic light scattering (DLS)[8] and neutron spin echo (NSE),[9] respectively. Because of such characteristic features in the network structure, physical properties, and biological compatibility, we believe that Tetra-PEGs are suitable candidates for (1) re-examination of the theories of rubber elasticity, (2) artificial organs such as muscle and cartilage, (3) gas-separation membrane in harsh conditions, (4) exploration to molecular sieves, and so on. References [1] Y. Okumura, and K. Ito: Adv. Mater. 13, 485-487 (2001). [2] J. P. Gong, Y. Katsuyama, T. Kurokawa, and Y. Osada: Adv. Mater. 15, 1155-1158 (2003). [3] K. Haraguchi, and T. Takehisa: Adv. Mater. 14, 1120-1124 (2002). [4] T. Sakai, T. Matsunaga, Y. Yamamoto, C. Ito, R. Yoshida, S. Suzuki, N. Sasaki, M. Shibayama, and U. Chung: Macromolecules 41, 5379-5384 (2008). [5] M. Shibayama: Soft Matter 8, 8030–8038 (2012). [6] T. Matsunaga, T. Sakai, Y. Akagi, U. Chung, and M. Shibayama: Macromolecules 42, 6245-6252 (2009). [7] H. Asai, K. Fujii, T. Ueki, T. Sakai, U. Chung, M. Watanabe, Y. S. Han, T. H. Kim, and M. Shibayama: Macromolecules 45, 3902-3909 (2012). [8] H. Asai, K. Nishi, T. Hiroi, K. Fujii, T. Sakai, and M. Shibayama: Polymer 54, 1160-1166 (2012). [9] T. Hiroi, M. Ohl, T. Sakai, and M. Shibayama: Macromolecules ASAP(2014).
L-13 INTERACTION OF POLYIONS WITH POLYELECTROLYTE HYDROGELS
A.B. Zezin, V.B. Rogacheva, O.A. Novoskoltseva
Lomonosov Moscow State University, Moscow, Russia [email protected]
The interaction between lightly cross-linked polyelectrolyte hydrogels and oppositely charged water soluble species (such as linear polyions, dendrimers, proteins and amphiphilic block-copolymers) is discussed. The massive samples of the highly swellable gels with the degree of swelling H 102103 were used. This gave us the possibility to observe easy the transformation of gel sample in the course of the interpolyelectrolyte reaction. We stated that such hydrogels are strongly collapsed as a result of the interpolyelectrolyte reaction. The macroscopically two-phase systems of core-shell type with the sharp boundary between the phases forming in the process were shown to be stable. This opens new potentialities to create the multilayered structures with the given nature and thickness of alternative shells. Kinetics and mechanism of the transfer of charged species into polyelectrolyte hydrogels are discussed on a basis of the frontal heterogeneous reactions. This approach proposes that the reaction proceeds via the conversion of the originally highly swollen hydrogel phase (H 103) into the newly formed compact low swollen (H 1) interpolyelectrolyte complex. It was found that the mechanism of charged species uptake by the oppositely charged hydrogels is changed from the frontal heterogeneous reaction to the conventional diffusion when the interpolyelectrolyte interaction is weakened. It can be achieved for instance via the addition of a lot amount of simple salt. In doing, so one can significantly reduce the value of hydrogel collapse. At such conditions the unfavorable contribution of excess network collapse will decrease and the free energy of mixing will become the dominative factor. Some possibilities of practical usage of complex hydrogels are discussed as well. This work was supported by the Russian Foundation for Basic Research, project № 12-03-00705-a.
ORAL PRESENTATIONS
O-01 CONFORMATION SPECIFIC THERMAL-RESPONSIVE POLYPEPTIDES MATERIALS
Z. Li
Institute of Chemistry, Chinese Academy of Sciences [email protected]
Environmentally stimuli-responsive polymers are currently a center of active research in nano- and biotechnology. In contrast to conventional polymers, responsive biopolymers are greatly desirable for biomedical applications. Synthetic polypeptides have been studied for decades to construct functional materials for biomedical applications. Adding additional stimuli-responsive moieties to polypeptides would be desirable to make intelligent biomaterials based on natural -amino acid. Herein, we reported a simple strategy to prepare nonionic thermal-responsive polypeptide made from methylated di- and tri-(ethylene glycol) functionalized L-glutamic acid. The pegylated L-glutamic acids were prepared by direct coupling between methylated ethylene glycols and L-glutamic acid via sulfuric acid catalyzed esterification. These amino acids were then converted into corresponding N-carboxyanhydrides (NCAs) using triphosgene in THF. Using different monomer to initiator ratio, we prepared several homopolypeptides and random copolypeptides with different chain lengths and narrow PDIs. We found that poly-L-EG2Glu and poly-L-EG3Glu, which contained two and three ethylene glycol units, respectively, displayed a reversible lower critical solution behavior (LCST) in water and buffer solution. In addition, both samples adopt -helical conformation in water, but the secondary structure of poly-L-EG2Glu strongly depended on sample history. CD measurements revealed that polyEG3Glu formed stable -helix in water with 100% helicity, and its secondary structure was independent of temperature. Surprisingly, it was found that the thermal-responsive properties of both polyEG2Glu and polyEG3Glu not only depended on monomer structures but also relied on the regularity of secondary structure. Only samples having stable a-helical structures can have well-defined LCST. Also, the LCST can be tuned via copolymerization of different EGxGlu-NCA at different ratio. Furthermore, we prepared three alkyl-polypeptide (AP) amphiphiles using alkyl amine as initiator via ring-opening polymerization (ROP) of -amino acid N-carboxyanhydride (NCA). The polypeptide segment was composed of diethylene glycol monomethyl ether functionalized poly-L-glutamate (poly-L-EG2Glu). These AP amphiphiles can spontaneously self-assemble into transparent hydrogels in water. These hydrogels showed shear thinning properties, and their strength can be modulated by hydrophobic alkyl tails. CryoTEM and AFM characterizations suggested these hydrogels were formed by nanoribbons arising from intermolecular interactions between nonionic poly-L-EG2Glu segments. References:
1. Shen, J.; Chen, C.; Fu, W.; Shi, L.; Li, Z. Langmuir 2013, 29, 6271-6278. 2. Fu, X.; Shen, Y.; Fu, W.; Li, Z. Macromolecules 2013, 46, 3753-3760. 3. Chen, H.; Xia, L.; Fu, W.; Yang, Z.; Li, Z. Chem. Commun. 2013, 49, 1300-1302. 4. Chen, C.; Wu, D.; Fu, W.; Li, Z. Biomacromolecules 2013, 14, 2494-2498. 5. Chen, P.; Li, C.; Liu, D.; Li, Z. Macromolecules 2012, 45, 9579-9584. 6. Chen, C.; Wang, Z.; Li, Z. Biomacromolecules 2011, 12, 2859-2863.
Acknowledgement. This work was supported by National Natural Science Foundation of China (50821062, 91027043).
O-02 ENCAPSULATION OF POLYMERIC NANOPARTICLES VIA EMULSION TECHNIQUES
M. Ayoub
Department of Polymers and Pigments, National Research Center, Dokki, Cairo, Egypt [email protected]
In Emulsion preparation, the most important consideration is the stability, which is characterized by; the absence of coalescence of dispersed phase, absence of creaming, maintenance of elegance, odour, colour and other physical properties. Synthesis of nanoparticles(NPs) by emulsion techniques is not only are of basic scientific interest but also have resulted in encapsulate the various types of drugs. The aim of the present work is to achieve the nanosize particles by emulsion to emulsion and microemulsion techniques to encapsulate hydrophilic and hydrophobic substance. Several factors(stirring time, stirring speed, polymers and several kinds of stabilizer concentration..etc) influencing the size of particles were investigated . The encapsulation efficiency of obtained particles was estimated using U.V. analysis and Transmission Electron Microscopy (TEM). It is obvious that, the prepared particles are submicron in size and spherical in shape. It can be concluded that the emulsion to emulsion and microemulsion techniques are succeeded in entrapment of both hydrophilic and hydrophobic drugs resulting in high entrapment efficiency more than 85%.
O-03 USING MULTI-DETECTOR GPC FOR ADVANCED POLYMER CHARACTERISATION
B. Bartylla1, K. Svirskiy2
1 - Agilent Technologies, Germany 2 - Agilent Technologies, Russia
Gel Permeation Chromatography (GPC) is the established technique for measuring Molecular Weight Distributions in the polymer industry. However conventional GPC only provides Molecular Weights which are relative to the standards used for calibration. The development of new polymers with more complicated structures means that there is an increasing need for advanced detectors that give absolute and/or accurate Molecular Weights, and structural information. Adding molecular weight sensitive detectors (Laser Light Scattering and/or Viscosity detectors) to the conventional GPC experiment enables the user to generate true molecular weights. In addition you can get valuable structural information such as molecular size and branching By adding 1 or more detectors (laser Light scattering and viscosity) to the GPC experiment we obtain advanced information compared to conventional GPC. In addition to the accurate and absolute molecular weight and MW distribution (MWD) we obtain information about branching across the polymer distribution which can be compared between samples. By applying a branching model we can also calculate the branching frequency across the MWD. In addition, by using a Light Scattering Detector with more than one angle we can obtain a size measurement Rg (Radius of Gyration). The Multi Detector GPC experiment enables the Polymer Chemist to obtain true molecular weight values from the experiment and generate structural data. Comparison of this data between samples can be invaluable when investigating and developing new polymers, and establishing batch to batch reproducibility and polymer quality in a production environment. The ability to investigate the structural properties of polymers using advanced detection GPC enables improved feedback to R&D projects, troubleshooting polymer performance issues, and allows for better characterization and breakdown of unknown materials.
O-04 SELF-ASSEMBLY OF CHROMOPHORE MOIETIES AS A MEANS FOR PREORDERING IN MOLECULAR DESIGN OF POLYMER
MATERIALS WITH QUADRATIC NONLINEARITY
O.D. Fominykh, A.V. Sharipova, M.Yu. Balakina A.E. Arbuzov Institute of Organic and Physical Chemistry of Kazan Scieitific Center of Russian Academy of Sciences
To exhibit the quadratic nonlinear optical (NLO) response polymer material with incorporated organic chromophores should be non-centrosymmetric, what is achieved by the dipole chromophores orientation in the applied electric field. The material NLO activity is determined, in particular, by the chromophore concentration; when it is rather high the problem of minimization of undesirable dipole-dipole interaction of the chromophores becomes crucial. One of the ways to avoid this problem is to synthesize polymers with dendritic multichromophore fragments, allowing for preordering the chromophore units. Molecular modeling plays quite important role in planning the synthesis of NLO polymers and hence in optimization of their NLO response. Earlier [1] we have performed the modeling of epoxy-based oligomers with dendritic fragments containing azo-chromophores as NLO units. In the course of Conformational Search, performed using MacroModel program package [2], the conformers of the studied oligomers were found, containing
stacking-arranged plain chromophores with almost parallel dipole vectors (see Figure 1). The distance between the chromophore planes is about 4 Å, which is characteristic for van-der-Waals interactions. Here we focus our attention on the study of peculiarities of bonding in such stacking-arranged chromophore dimers by means of quantum-chemical calculations at different computational levels: HF and DFT using different functionals, including those accounting for dispersion corrections, such as B97D, CAM-B3LYP, wB97D-2X and M06-2X. The account of dispersion was found to decrease the chromophores interplanar distance by ~0.8 Å compared to that estimated at HF level of calculation. Bonding in intermolecular region was studied in the framework of topological analysis of
electron charge density distribution using Atoms in Molecules approach [3]. In the intermolecular region (3; -1) critical points were observed giving evidence of bonding; electron charge density values in these points are typical for van-der-Waals interactions. Molecular electric properties, dipole moment, (hyper)polarizability, for both azochromophore and stacking dimers were calculated quantum-chemically at HF//TDHF//aug-cc-pVDZ and B97D//TDHF//aug-cc-pVDZ levels using FireFly program package [4]. The value of first hyperpolarizability of the stacking structure was found to increase negligibly compared to that of one chromophore when estimated at B97D level; at HF level this effect being overestimated. Assuming the disturbance of -conjugation in the chromophores due to the stacking structure formation, we have performed the simulation of the Raman spectra for the chromophore and stacking dimer using wave function obtained at B97D level. We observed significant decrease of Raman activities of characteristic vibrations in the chromophore in stacking dimer relative to those of separate chromophore, what is the evidence of -conjugation disturbance. In addition we have analyzed the HOMO and LUMO frontier orbitals isodensity surfaces for azochromophore and corresponding stacking dimer.
[1] M.Yu. Balakina, O.D. Fominykh. Macromol. Symp., 2012, V.316, P.52-62. [2] MacroModel, version 9.8, Schrodinger, LLC, New York 2010. [3] R.F.W.Bader, Atoms in Molecules, A quantum theory, Clarendon Press, Oxford, 1990, 532 p. [4] Alex A. Granovsky, Firefly version 8.0.0, http://classic.chem.msu.su/gran/firefly/index.html
Fig. 1. Epoxy-amine oligomer with dendritic azochromophore-containing fragments.
O-05 MELT OF POLYMER RINGS: THE DECORATED LOOP MODEL
S. Obukhov1, A. Johner2, J. Baschnagel2, H. Meyer2, J.P. Wittmer2 1 - University of Florida
2 - Institut Charles Sadron, Strasbourg [email protected]
Melts of unconcatenated and unknotted polymer rings are a paradigm for soft matter ruled by topological interactions. We propose a description of a system of rings of length N as a collection of smaller polydisperse Gaussian loops, ranging from the entanglement length to the skeleton ring
length ∼ N^(2/3), assembled in random trees. Individual rings in the melt are predicted to be
marginally compact with a mean square radius of gyration R^2~N^(2/3) (1-const·N^(-1/3)).
We demonstrate that simple power laws for asymptotically long rings come with extremely sluggish crossovers. We argue that current experiments and computer simulations merely deal with crossover regimes. The calculated crossover functions allow for a satisfactory fit of simulation data.
O-06 NOVEL WATER-SOLUBLE REGULAR POLYIMIDE BRUSHES AS NANOCONTAINERS FOR CYANOPORPHIRAZINE AGENTS OF
PHOTODYNAMIC THERANOSTICS
A.V. Yakimansky1, T.K. Meleshko1, D.M. Ilgach1, N.N. Bogorad1, N.V. Kukarkina1, T.D. Ananjeva1, L.G. Klapshina2, S.A. Lermontova2, I.V. Balalaeva3, W.E. Douglas4
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, 199004 St. Petersburg, Russia
2 - Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Tropinin str. 49, GSP-445, 603600 Nizhny Novgorod, Russia
3 - Lobachevsky State University of Nizhnii Novgorod, Institute of Living Systems, Gagarin pr. 23, 603950 Nizhny Novgorod, Russia
4 - CNRS UMR 5253, Universite Montpellier II, Place E. Bataillon, 34095 Montpellier cedex 5, France [email protected]
An approach to the synthesis of new regular polyimide-graft-(polymethacrylic acid) brushes is elaborated, including 1) synthesis of multicenter polyimide macroinitiators, 2) controlled ATRP of tert-butylmethacrylate on the prepared macroinitiators, and 3) protonolysis of tert-butyl ester groups of side chains of thus obtained polyimide-graft-poly(tert-butylmethacrylate). Experimental conditions for attaining complete conversions of the first and the third stages of the process are determined by means of 1H NMR and FTIR-spectroscopy. Polymer products of the first and the second stages of the process, as well as poly(tert-butylmethacrylate) side chains cleaved from the polyimide-graft-poly(tert-butylmethacrylate) copolymers by complete decomposition of the polyimide backbone under alkaline hydrolysis conditions, are characterized by GPC. Kinetics of poly(tert-butylmethacrylate) chain growth on a polyimide macroinitiator under ATRP conditions is studied. The obtained results prove a controlled character of the ATRP process and regular structure of the synthesized graft-copolymers. A regular brush character of the synthesized polyimide-graft-(polymethacrylic acid) copolymers is proved by the data of TEM (Fig. 1) obtained for conjugates of these brushes with Yb(III)-cyanoporphirazine complexes.
a b Fig. 1. TEM micrograph (a) and a schematic representation (b) of the architecture of a conjugate between a polyimide-graft-(polymethacrylic acid) molecular brush and Yb(III)-cyanoporphirazine complexes. Compared to other water-soluble polymers, e.g., polyethyleneglycol, used for solubilization of hydrophobic molecules, the obtained polyimide-graft-(polymethacrylic acid) nanocontainers with cyanoporphirazines and their Yb(III)-complexes incorporated into the space between side chains of a molecular brush provide a much more efficient transport of the indicated photodynamic theranostics agents into tumor cells. The work is supported by the Russian Foundation for Basic Research (projects nos. 11-03-00353-а, 12-04-90031-Bel_а, and 14-03-31809-mol-a).
O-07 МACROMOLECULAR CLOTHES OF NANOPARTICLES: THEIR DRESSING UP, UNDRESSING, THE SELECTION, AND THE ALTERING
OF THE CLOTHES
I.M. Papisov Moscow Automobile and Road State Technical University (MADI), Moscow, Russian Federation. 125319 Moscow
Leningradsky prosp. 64 [email protected]
Metal nanoparticles are capable to cooperative non-covalent interactions (including hydrophobic ones) with appropriate macromolecules followed with the “dressing-up” of the particles with protective polymer screens (“shadows”). The cooperative character of the interactions between polymer chains and extended objects is typical of polymers. The role of the interactions in the synthesis and the behavior of nanocomposites (“dressed” nanoparticles represent nanoparticle – macromolecule complexes) is to be regarded. In water media, neutral water-soluble polymers, negatively and positively charged polyelectrolytes, as well as interpolymer complexes (IPC), can be used to “dress up” metal nanoparticles. The IPC are particularly effective due to their amphiphilic nature and the capacity of self-assembling on the surface of a nanoparticle. The "dressing up". Complex formation between long polymer chain and a nanoparticle can be considered as the adsorption of the nanoparticle on unidimentional adsorbent. Due to the cooperative nature of the interactions between the surface of the nanoparticle and polymer chain, the stability of the complex exponentially increases with the increase in surface area of the particle. Therefore, the probability of "mutual recognition" of a macromolecules and a nanoparticle changes rapidly from almost zero to almost unity in a narrow size range of the nanoparticle. At the values of free energy of the interaction ΔG around 10-3 - 10-4 J/m2, the dressing up" s becomes thermodynamically favorable in the range of nanoparticle’s diameter from 1 to 10 nm. This is the reason for the formation of metal sols with narrow size distributions in the processes of the reducing of metal ions in polymer solutions. (Such kind of processes we termed "pseudo - template"). Similar mechanism can be realized in the processes of electro –and electrochemical reduction of metal ions in polymer solutions rtsulting in the formation of polymer - metal nanocomposites on cathode surface. The "undressing". If the sol of polymer - metal nanocomposite was obtained at some conditions, and then placed in other conditions in which corresponding polymer - nanoparticle complex is less stable, then the "undressing" of the nanoparticles should be occurred. If the conditions have changed slightly, then the smallest particles "undress", grow due to their aggregation, and “dress up” again. As a result, the average size of particles is also increased. In the case of strong and rapid change in the conditions, the "undressing" can be irreversible leading to the destruction of the sol. The “selecting of clothes” . The cooperative nature of the interactions between nanoparticles and macromolecules is the reason for high selectivity of the interactions with regard to chemical structure of polymer chains. The selectivity can be realized in two types of processes. (1) Nanoparticle makes a choice, which one of two (or more) macromolecules of different structures is preferable to be recognized with the creation of protective screen. (2) If a nanoparticle have been "dressed" with some polymer screen, the nanoparticle can “change the clothes" by replacing the polymer in the screen with more strong complex forming polymer. The “altering of the clothes”. It is well known that catalytic activity and selectivity of polymer – protected metal nanoparticles is increased with the decrease of their size. In some cases the polymer formed the screen can be served itself as the substrate of nano-catalyst. As a result, the nano-catalyst modifies chemically the polymer thus “altering of the clothes” of the nano-catalyst. For example , copper nanoparticles stabilized with poly(N-vinyl pyrrolidone) actively catalyze the hydrolysis of lactam cycles in monomer unites of the polymer. The polymer analogous reaction takes place only in macromolecules formed the screens, whereas high excess of free polymer present in the reaction medium. A necessary condition of high conversion in such kind of reactions is step-by-step substitution of modified polymer in protective screens with non- or less modified polymer. The substitution is possible if the stability of polymer – particle complex decreases in course of the catalytic polymer analogous reaction.
O-08 CONFORMATIONAL BEHAVIOR OF BRANCHED WEAK POLYELECTROLYTES
F. Uhlik
Charles University [email protected]
Polyelectrolytes are polymers with ionizable groups. They can be either strong (also called quenched, e.g. polystyrene sulfonic acid) or weak (also called annealed, e.g. po �lyacrylic acid) . While strong polyelectrolytes are fully ionized upon dissolution, the degree of ionization of weak polyelectrolytes is coupled with conformations and can be influenced by both pH and ionic strength. Water solubility and responsiveness to external stimuli makes weak polyelectrolytes very attractive for applications. Moreover, the behavior of weak polyelectrolytes is quite complex especially when conditions like large Bjerrum or Debye lengths, poor solvent for undissociated polyelectrolyte or polymer branching are considered. In this contribution I show an efficient simulation technique based on hybrid Monte Carlo in reaction ensemble suitable for studying weak polyelectrolyes under various conditions together with results for some types of branching (e.g. polymer stars, combs or brushes) to illustrate both the capability of the method and the unusual properties of weak polyelectrolytes.
O-09 KINETICS OF COLLAPSE AND AGGREGATION IN THERMORESPONSIVE MICELLAR BLOCK COPOLYMER SOLUTIONS
C.M. Papadakis1, J. Adelsberger1, I. Grillo2, A.M. Bivigou-Koumba3, A. Laschewsky3,
P. Mueller-Buschbaum1 1 - Technische Universitaet Muenchen, Physik-Department, Garching, Germany
2 - Institut Laue-Langevin, Large Scales Structures Group, Grenoble, France 3 - Universitaet Potsdam, Institut fuer Chemie, Potsdam-Golm, Germany
Thermoresponsive, polymeric hydrogels respond in a controlled and reversible way with a volume change to a small change of temperature across the cloud point. These switchable and nanostructured materials are of great interest for controlled molecular ultrafiltration. A widely used thermoresponsive polymer is poly(N-isopropylacrylamide) (PNIPAM) which exhibits a cloud point at 32 °C. We investigate self-assembled, physically crosslinked thermoresponsive hydrogels formed by amphiphilic, symmetric triblock copolymers having short, fully deuterated polystyrene (P(S-d8)) end blocks and a large (PNIPAM) middle block. We focus on the structural properties as a function of temperature [1] as well as on the kinetics of the collapse of the micelles and their subsequent aggregation [2,3]. Small-angle neutron scattering (SANS) with contrast matching allowed us to reveal the core-shell structure of the micelles as well as the network structure. We found that, at the cloud point, the shell collapses and the distance between the P(S-d8) cores shrinks abruptly [1]. The changes are reversible upon cooling. Using in-situ, real-time SANS following a temperature jump across the cloud point, we characterized the collapse and the subsequent aggregation behavior in a micellar solution in D2O [2,3]. The collapse of the micellar shell is extremely fast (< 1 s). The aggregation process of the collapsed micelles is complex and involves several steps, such as the formation of small and loosely packed aggregates, their densification and eventually their coagulation. Thus, large aggregates are only formed after a certain time which may be at the origin of the slow reswelling behavior after prolonged heating of such solutions to high temperatures. Time-resolved SANS thus gives detailed information on the structure and dynamics as well as on the kinetics of switching.
Figure 1. Schematics of the setup for time-resolved small-angle neutron scattering measurements of the collapse and aggregation behavior of a thermoresponsive polymer during a temperature jump through the cloud point. The shell of the micelles formed by P(S-b-NIPAM-b-S) in aqueous solution collapses very rapidly. The aggregation of the collapsed micelles proceeds via a multi-step process [2].
This work was supported by the DFG priority program SPP1259 “Intelligente Hydrogele”.
1. Adelsberger, J.; Papadakis, C.M. et al., Macromolecules, 43, 2010, 2490. 2. Adelsberger, J.; Papadakis, C.M. et al., Macromol. Rapid Commun. 33, 2012, 254. 3. Adelsberger, J.; Papadakis, C.M. et al., Soft Matter 9, 2013, 1685.
O-10 SENSOR SWITCHES BASED ON ADSORBING MINORITY CHAINS IN BRUSH: TRANSITION SHARPNESS AND TIME RESPONSE
L.I. Klushin1, A.M. Skvortsov2, A.A. Polotsky3, S. Qi4, F. Schmid4
1 - American University of Beirut, Physics Department, Beirut, Lebanon 2 - Chemical-Pharmaceutical Academy, St. Petersburg, Russia
3 - Institute of Macromolecular Compounds RAS, Saint-Petersburg, Russia 4 - Johannes-Gutenberg University, Institute for Physics, Mainz, Germany
Mixed polymer brushes with two chemically different polymers grafting onto the same substrate are used as switches [1,2]. These are typically made of two different polymer species, hydrophobic and hydrophilic with a composition close to 50:50. Phase segregation causes the switching of the brush exposing one or the other component to the surrounding medium. Existence of kinetically frozen metastable states at lateral nanoscale segregation leads to a relatively slow response on the timescale from minutes to hours. The temperature interval where the transition occurs is . We suggest a new class of brush-based switches based on a radical change in conformations of adsorption-active minority chains in a brush. A small change in temperature or solvent composition may lead to a sharp conformational transition from an adsorbed state whereby the switch chain is completely hidden inside the brush thickness to a exposed state in which the free end of the switch chain is localized at the outer surface of the brush. Strong sharpness results from an underlying first order phase transition with a corresponding bimodal distribution function, in contrast to a continuous adsorption transition of an isolated grafted chain in the absence of a brush. If each minority chains has an active group attached to its free end, the brush switches between two states: one with all active groups located near the solid substrate fully within the brush, and the other with all the groups exposed at the outer brush interface. In contrast to the known mixed brushes the change in the bulk properties of the proposed systems is limited. However, the active end-groups can serve as sensors triggering an immune-like response or a detectable change in optical properties. The proposed switches possess two main advantages. First, the transition is sharp and can be induced by a temperature change of only a ten degrees, as attested and utilized by polymer chromatography in mixed eluents [3]. Second, the characteristic time of the conformational change is quite small: we estimate it as a fraction of a second. Hence the rate of change in the brush properties is actually limited by the rate of change in the external conditions. A conceptually similar conformational transition for adsorption-inactive minority brush chains of varying contour length was described theoretically [4] and then studied by simulations [5,6]. However, this effect cannot serve as a switching mechanism since the contour length is impossible to change in a controlled and reversible way. The focus of this work is to provide a theoretical description for the proposed class of sensor switches and clarify how the brush parameters (chain lengths of the majority and minority chains, grafting density) affect two main properties of the switch performance: the sharpness of the transition from one state to the other, and the time of response to a sudden change in the control parameters. We present an analytical theory and support it by SCF calculations and Langevin dynamics simulations. References: [1] M Cohen Stuart et al,Nature Materials, 9:101–113, 2010. [2] J Draper, I Luzinov, S Minko, I Tokarev, and M Stamm, Langmuir, 20, 4064, 2004. [3] AI Abdulahad and CY Ryu, J.Pol.Sci. B-Polymer Physics, 47, 2533, 2009. [4] AM Skvortsov, LI Klushin, and AA Gorbunov, Macromolecules, 30, 1818, 1997. [5] D Romeis and JU Sommer, J.Chem Phys, 139, 044910, 2013. [6] D Romeis, H Merlitz, and JU Sommer, J.Chem.Phys., 137, 064907, 2012.
O-11 COPOLYMER NANOPARTICLES FOR BIOMEDICAL APPLICATIONS
P. Stepanek, E. Jager, A. Jager, S. Petrova, Ch. De Garcia Venturini
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czeck Republic [email protected]
Recent advances in controlled and tailored production of polymeric nanoparticles make them very attractive objects for biomedical applications. These include in particular targeted drug delivery or diagnostic, therapeutic and theranostic applications. Nanoparticles can be created by direct synthetic routes or by physico-chemical processes of nanoassembly from preformed polymers. The latter approach offers a greater variety in the composition and detailed structure of nanoparticles as well as a greater control of their properties important for bioapplications such as biodegradability. Several types of surfactant-free nanoparticles obtained by nanoprecipitation will be described. Surfactant-free PLGA (poly(lactic-co-glycolic acid)) nanoparticles with hydrodynamic diameter between 25 and 100 nm were obtained by controlling the polymer concentration, choice of organic solvent, mixing different solvent, by changing temperature and ionic strength. This methodology has the advantage of scale-up production. The size of the nanoparticles is mainly dependent on the organic solvent, the solvent-water interaction is the main factor affecting the size independently of the nature of the biodegradable polymer. The polymer-solvent interaction does not play a substantial role in the dimension of the polymer colloids. pH-sensitive polymeric micelles degradable in an acidic environment were prepared from a newly synthesized series of amphiphilic diblock copolymers containing an acid-cleavable ketal linkage in their backbone. The amphiphilic block copolymers based on poly(ε-caprolactone) (PCL) and poly(ethylene oxide) (PEO) are of special interest for their environmental, biomedical and pharmaceutical applications. Indeed, PCL is aliphatic hydrophobic polyester with great potential as biomaterial due to its unique combination of biodegradability and biocompatibility. On the other hand, PEO is very flexible polymer, non-toxic and biocompatible, “non-biodegradable”, but bioeliminable due to its hydrophilicity. Surfactant-free, narrowly distributed, nanosized spherical particles have been produced from a new aliphatic biodegradable copolyester PBS/PBDL (poly(butylene succinate-co-butylene dilinoleate)) by applying a single-step nanoprecipitation protocol. The nanoparticles comprise a porous core conferring a non-compact characteristic. Their porosity enables water to be entrapped which is responsible for their pronounced stability and relatively fast degradation as followed by size exclusion chromatography. The polymeric nanoparticles could be loaded with the hydrophobic model drug paclitaxel (PTX) with an encapsulation efficiency of ~95% and drug loading content of ~6–7% wdrug/wpolymer. The drug encapsulation and release modifies the inner structure of the nanoparticles; encapsulation leads to replacement of the entrapped water by the hydrophobic drug and to shrinking of the nanoparticles, due to favorable drug–polymer hydrophobic interactions. Cell viability experiments demonstrated that the nanoparticles are biocompatible and non-toxic, making them good candidate for applications in nanomedicine. Support by the Grant Agency of the Czech Republic (P208/10/1600) is gratefully acknowledged.
O-12 POLYELECTROLYTE COMPLEXES AS DRUG CARRIERS: PREPARATION AND PROPERTIES
M.Y. Gorshkova, I.F. Volkova, E.S. Grigoyan
A.V.Topchiev Institute of Petrochemical Synthesis Russian Academy of Science Moscow Russia [email protected]
Polyelectrolyte complexes (PECs) due to ability to change their properties under the external impulse could be considered as the example of so-called “smart systems”. Complexes formed from pH-sensitive polyions gains the pH-responsibility that made them particularly attractive for design of drug delivery systems. PECs formed by natural polymers or synthetic polymers that possess biological activity as well as pH-sensitivity are the most interesting for this application. Recently1 we studied the complex formation between synthetic polyacid, copolymer of divinyl ether - maleic anhydride (DIVEMA) and modified chitosan (MCts). Both components of studied system are water-soluble and biological active. Copolymer DIVEMA possesses its own antivirus, antitumor and immune stimulating activities and is used in design of delivery systems for drug and imaging agents. In water solution copolymer DIVEMA easily transforms into a polyanion with high density of charges due to hydrolysis of the anhydrous cycles. The MCts - modified N-(2-hydroxy-3-trimethylammonium)propyl chitosan used in present study as a polycation is combining such advantages of chitosan as its low toxicity, biocompatibility and biodegradability with solubility in water medium through the whole pH range. As both MCts and DIVEMA undergo pH-dependent ionization, the polyions could be formally related to weak polybase and weak polyacid, respectively. This is especially true for DIVEMA, while MCts s chain combines the properties of both weak and strong polybases. Numerous quaternized amino groups of MCts remain fully charged in the whole pH range and markedly affect the ionization of neighboring secondary amino groups. Formation of either soluble or insoluble MCts/DIVEMA complexes in aqueous and water–salt solutions was shown to be controlled by pH, ionic strength, a ratio of the oppositely charged groups, degree of polymerization of the chains and met to general rules of polyelectrolyte complexes behavior. The objective of the present study was to develop drug delivery system based on MCts/DIVEMA polyelectrolyte complexes. The anticancer antibiotic rubomicin (Rb) was used as a model drug. MCts/DIVEMA/Rb complexes have been prepared by mixing of the component solutions in neutral and slightly basic media. The MCts/DIVEMA ratio in the mixtures was varied from 1/1 to 10/1, whereas the amount of the drug was constant and Rb/DIVEMA ratio was equal 1/10. In neutral medium, as it followes from DLC data, the particle sizes of the drug-loaded complexes ranged from 200 to 400 nm with changes of MCts/DIVEMA ratio from 1/1 to 5/1 correspondingly. The further increasing in amount of MCts resulted to the formation of multimodal particles. The ionic strength is one of the most important parameters that controlled complexes properties therefore the behavior of the complexes in water-salt solutions was studied. It was shown that salt (KCl) concentration above 0.5M caused complexes dissolution. Importantly, MCts/DIVEMA/Rb complexes could sustain the ionic strength close to physiological one. The pH value that determines polyelectrolyte degree of ionization impacted on complexes stability and particle size. Namely, the complexes with MCts/DIVEMA ratio from 1/1 formed at pH 9 had a smaller size, than the ones formed in neutral medium. The decrease in pH value up to pH 5 caused the complexes dissolution. Thus the drug loaded MCts/DIVEMA PECs stable at physiological medium were prepared and their properties were investigated. The data obtained demonstrated the potential of the prepared PECs as a promising platform for development of biocompatible and pH-tunable drug delivery systems. 1 V.A. Izumrudov et al. / European Polymer Journal 49 (2013) 3302–3308
O-13 COMPUTER SIMULATION OF NEW TYPE OF BRANCHED PEPTIDES - LYSINE DENGRIGRAFTS
I.M. Neelov1,3, B.M. Okrugin2, S.G. Falkovich3 A.A. Darinskii3
1 - ITMO University, St.Petersburg, Russia; Institute of Macromolecular Compounds, St.Petersburg, Russia 2 - SPb State University, St.Petersburg, Russia
3 - Institute of Macromolecular Compounds, St.Petersburg, Russia [email protected]
Regularly branched lysine dendrimers were synthesized in the beginning of 1980th but they are much less known in comparison with PAMAM, PPI, carbosilane and other synthetic dendrimers. Lysine dendrimers were used as a branched core for multiple antigen peptides as antimictobial, antiviral and antiamyloid agents. Recently a new type of branched lysine peptides - lysine dendrigrafts were synthesized. Lysine dendrigrafts are almost regularly branched peptide structures consisting of linear lysine core and branched lysine repeat units. They could be considered as peptide dendrimers with linear lysine core and lysine branching units or as peptide brushes with short linear main chain and branched side groups consisting of lysine residues. Molecular dynamics simulation of lysine dendrigrafts was performed using simulation package GROMACS. A model with full atomic details and force field Amber99-SB-ildn were used. Systems consisting of a single dendrigraft molecule in cubic simulation cell filled with water molecules and counterions were studied. All terminal lysine groups (NH3
+) of dendrigrafts were positively charged. Counter ions (Cl-) were added to ensure electroneutrality of the system. In this study, we calculated structural characteristics of dendrigrafts of 1-3 generations, in particular, the radius of gyration, anisotropy of shape, radial distribution function for all dendrigraft atoms and for their charged end groups. The results were compared with corresponding characteristics for lysine dendrimers of similar molecular mass (1-5 generations). It was obtained that the spatial structure of lysine dendrigrafts has many similarities with the structure of lysine dendrimers. For example, the radius of gyration and its molecular mass dependence, anisotropy of shape, radial distribution functions are close to corresponding characteristics of lysine dendrimers of similar molecular mass. At the same time there are some essential differences between these systems. For example, radial distribution function (density profile) of lysine dendrigrafts does not have minimum for largest dendrigrafts studied, the distribution function of charged terminal groups for all dendrigrafts is not unimodal (as for dendrimers) but bimodal. This work was partly supported by RFBR grant 13-03-00728 and Government of Russian Federation grant 074-U01. Computational resources (“Lomonosov” supercomputer) have been provided by Moscow State University.
O-14 ON POLYMERIZATION OF VINYLCAPROLACTAM
H. Tenhu, M. Karesoja Department of Chemistry, Laboratory of Polymer Chemistry, PB 55, 00014 University of Helsinki, Finland
Interest on poly(vinyl caprolactam), PVCL, has been clearly increasing, most probably because it is generally considered as a biocompatible polymer.1 PVCL shows a LCST behaviour in water, however, the cloud point is dependent on the molecular mass. Several of the applications of the polymer have been based on macroscopic or micro(nano)scopic gels. Several methods for controlled polymerization of VCL have been investigated during the last few years, with reasonable success. Two cases will be discussed where PVCL has been prepared with acceptable results. In the first case, biocompatible and degradable mesoporous silica nanoparticles have been grafted with PVCL to prepare entities which could be utilized as switchable vehicles for low molar mass active substances. The grafting was conducted via surface initiated ATRP. To ensure the colloidal stability of the particles even at elevated temperature, short PEO blocks were bound to the chain ends with click chemistry. The homogeneity of the chains detached from the particle surfaces was reasonable, however, the polymerization itself is not too well controlled.2 The second case is on diblock copolymers. A multiresponsive polymer has been synthesized by first polymerizing VCL with MADIX, Then, the end group has been changed into an ATRP initiator and dimethylaminoethylmethacrylate has been polymerized. Of the methods we have tested so far MADIX seems to be the best one to create PVCL with a narrow molar mass distribution. The PVCLPDMAEMAs are multiresponsive i.e., while the cloud point of PVCL may be changed by changing the chain length, that of PDMAEMA is sensitive to pH. PDMAEMA as a weak polybase has been shown to complex DNA and transfect it into cell nuclei.3 This fact makes the diblock copolymers most interesting. Changes of physical properties of aqueous solutions/dispersions upon increasing temperature will be shortly discussed. Enthalpy change associated with the collapse of the polymers is certainly informative, whereas problems with measuring the zeta potentials need careful considerations. 1Vihola, Henna; Laukkanen, Antti; Valtola, Lauri; Tenhu, Heikki; Hirvonen, Jouni; Biomaterials (2005), 26(16), 3055-3064
2Karesoja, Mikko; McKee, Jason; Karjalainen, Erno; Hietala, Sami; Bergman, Lotta; Linden, Mika; Tenhu, Heikki; Journal of Polymer Science, Part A: Polymer Chemistry (2013), 51(23), 5012-5020
3Alhoranta, Anu M.; Lehtinen, Julia K.; Urtti, Arto O.; Butcher, Sarah J.; Aseyev, Vladimir O.; Tenhu, Heikki; Biomacromolecules (2011), 12(9), 3213-3222
O-15 EFFECTIVE INTERACTIONS BETWEEN BRUSH-COATED NANOPARTICLES IN POLYMER SOLUTIONS
S.A. Egorov1, J.U. Sommer2, K. Binder3
1 - University of Vrginia, Chemistry Department, Charlottesville, USA 2 - Technical University, Polymer Institute, Dresden, Germany
3 - University of Mainz, Physics Institute, Mainz, Germany [email protected]
Using Density Functional Theory and Molecular Dynamics simulations, we systematically study the effective pair potential between two particles induced by unconnected monomers and by polymers at various polymer concentrations, particle sizes of nano-scale, and polymer-particle interactions. In the case of athermal interactions, we verify that the entropic depletion forces between two nanoparticles inside a solvent of unconnected monomers oscillate in accordance with the radial distribution of monomers around one nanoparticle, and that the strength of polymer-induced entropic depletion forces raises linearly with the increase of nanoparticle size. When introducing direct attractive interactions between nanoparticles and polymers, the adsorption of polymer segments on the surface of each nanoparticle induces repulsive forces between the nanoparticles which are shown to eliminate the depletion attractions. Further adsorption by enhancing the attraction strength between polymer and nanoparticle leads to the formation of thin, enthalpically stable polymer-layers on the surfaces of nanoparticles. In this way, the nanoparticle size is effectively increased and the depletion attraction reappears at a somewhat increased particle distance. The observed phenomena become increasingly pronounced at higher polymer concentrations.
O-16 IONIZABLE POLYMER BRUSH. SELF-CONSISTENT FIELD MODEL
E.B. Zhulina, O.V. Borisov
Institute of Macromolecular Compounds of the Russian Academy of Sciences, St.Petersburg, Russia, and St.Petersburg National Research University of Information Technologies, Mechanics and Optics,, St.Petersburg, Russia
We present the analytical self-consistent field (SCF) model of a planar weak polyelectrolyte brush. The model describes the chain conformations in terms of trajectories and uses the strong stretching approximation for tethered chains. The electrostatic interactions are incorporated on the Poisson-Boltzmann level. We discuss the generic properties of such brushes (the electrostatic potential, the salt-mediated ionization, the thermal fluctuations, etc.), and systematically compare them with features of strong polyelectrolyte brushes. We demonstrate that in contrast to uniform ionization of macromolecules in the charged and salt –dominated brush regimes, ionization of polyion in the osmotic regime is quite inhomogeneous. Moreover, the degree of ionization of the terminal segment at the brush periphery and that of the monomers near the grafting surface obey different scaling dependences.
O-17 THE SUPRAMOLECULAR ASSEMBLY OF INTRINSICALLY DISORDERED NUCLEOPORIN DOMAINS IS TUNED BY COHESIVENESS
– IMPLICATIONS FOR NUCLEAR PORE PERMEABILITY
R.P. Richter1, N.B. Eisele2, S. Frey3, D. Goerlich3 1 - CIC biomaGUNE, San Sebastian, Spain; Universite de Grenoble, Department of Molecular Chemistry, Grenoble,
France; Max Planck Institute for Intelligent Systems, Stuttgart, Germany 2 - CIC biomaGUNE, San Sebastian, Spain
3 - Max Planck Institute for Biophysical Chemistry, Department for Cellular Logistics, Goettingen, Germany [email protected]
Nuclear pore complexes (NPCs) control the exchange of macromolecules between the cytoplasm and the nucleus of eukaryotic cells, a process that is essential in all higher organisms. Transport occurs through nuclear pores, channels of about 40 nm in width and length. The pore is filled with heterogeneous, flexible polymers – intrinsically unfolded nucleoporin domains rich in phenylalanine-glycine dipeptides (FG domains) – that are grafted to the channel walls. It is known that this filling makes transport size and species selective, but the physical mechanisms behind selectivity remain poorly understood. There is increasing evidence that selective transport requires cohesive FG-domain interactions. To understand the functional roles of cohesiveness, we studied planar monolayers of end-grafted FG domains with quantitatively tunable grafting density as a bottom up nanoscale model system of the permeability barrier. The physico-chemical properties of the model films was analyzed quantitatively and in detail (incl. film assembly kinetics, morphology and mechanical properties, lateral mobility of FG domain chains and binding of nuclear transport receptors) with a toolbox of surface sensitive techniques (incl. spectroscopic ellipsometry, AFM, QCM-D and FRAP). Based on this analysis and comparison of the data with polymer theory, we propose that cohesiveness is tuned to promote rapid assembly of the permeability barrier and to generate a stable and compact pore-filling meshwork with a small mesh size. Our results highlight the importance of weak interactions, typically a few kT per chain, for biological function and contribute important information to understand the mechanism of size-selective transport through the NPC. This work was funded by the European Research Council (Starting Grant 306435) and the Spanish Ministry of Economy and Competitiveness (RYC2009-04275 and MAT2011-24306).
O-18 THE PECULIARITY 0F THE PHASE TRANSITIONS IN HOMOLOGOUS SERIES OF LONG-CHAIN MOLECULAR CRYSTALS
V.A. Marikhin1, V.M. Egorov1, L.P. Myasnikova1, E.I. Radovanova1, B.Z. Volchek2,
D.A. Medvedeva2, E.N. Vlasova2 1 - Ioffe Physical Technical Institute of the Russian Academy of Sciences, 194021 St.Petersburg, Polytekhnicheskaya
26, Russia 2 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St.Petersburg, Bolshoy pr.
31, Russia [email protected]
The peculiarities of the phase transitions (structural transition, PHT-1, and order-disorder transition, PHT-2) in the homologous series of the normal paraffins, alcohols, alcanodiols, mono and dicarbon acids is investigated with the help DSC and Fourier-IR spectroscopy. The volume energy of the crystals was varied by the change in the length of methylene sequences. The change in the type of the end groups is influenced the crystal surface energy, especially in the case when the hydrogen bonds are formed between hydroxyl or carboxyl groups. The attribution of endo- and exo- Cp- peaks to PHT-1 and PHT-2 is rigorously proven with the help of DSC. For the first time the analysis of Cp-profiles is carried out on the base of the Landau theory (for PHT-2 transition) and the theory of self-consistent field (for the diffused PHT-1 peaks). The relative contribution of the methylene sequences and the end groups to the change of the conformation entropy of PHT-1 transition is found. The sizes of the new phase nuclei that are generating in the volume of the initial phase are determined for the PHT-1 transition. These varied from 50 nm3 up to 350 nm3, i.e. accounting tens-hundred molecules in the nuclear cross section. The well pronounced dependence of the nuclei size from the length of the methylene sequences and even- odd number of carbon atoms in the chains is observed. The reduction of the PHT-1 transition enthalpy with the increase of the end group size is found that is obviously associated with the decrease in interpacking density of the methylene segments inside of the lameli that takes place up to the moment of the mesophase formation. The observed reduction is caused by the defects that are formed because of the elastic stress generation during the interpacking of the large end groups. The transformation kinetics of the orthorhombic sub-cells to the hexagonal ones in the lamellar crystalline core in the vicinity of PHT-1 transition, the formation and change in the extended hydrogen bond sequences between the end groups, as well as the generating of the irregular conformers upon heating in the vicinity between the PHT-1 and PHT-2 transitions are investigated with the help of IR-spectroscopy. The authors acknowledge the support of a research grant from the Russian Foundation of Basic Research (the project No 13-03-00634/14)
O-19 MOLECULAR MOBILITY IN THE PRE-SURFACE LAYERS OF UHMWPE GEL-CRYSTALLIZED FILMS
L.P. Myasnikova1, Yu.M. Boiko1, D.V. Lebedev1, V.A. Marikhin1, E.I. Radovanova1,
P.N. Yakushev1, E.I. Ivankova2 1 - Ioffe Physical Technical Institute RAS, Solid State Physics, St.Petersburg. Russia
2 - Institute of Macromolecular Compounds RAS, Physical Department, St.Petersburg, Russia [email protected]
UHMWPE is a polymeric material with unique properties enabling one to produce ultrahigh strength high modulus fibers via gel-technology. The strength of the fibers is higher than that of the best steels by a factor of 2, while the specific weight is 8 times smaller. Then these fibers are irreplaceable reinforcement material in the composites with high ballistic characteristics. However the tensile strength and the modulus of the commercial and even lab-scale UHMWPE high performance fibers remain lower than the theoretical estimates. What is a reason? It is generally accepted that the failure begins from the surface and is initiated by surface defects. The aim of this work was then to investigate the specific features of the pre-surface layers of the UHMWPE ultradrawn high strength high modulus films obtained from the mineral-oil-based and decaline-based xerogels. The molecular mobility of the pre-surface layers was studied with the help of thermoluminescent method using a Nanoluminograph (PlasmaChem GmbH, Berlin, Germany). The glow curves are recorded upon the heating of the UHMWPE undrawn and drawn samples preliminary vacuumed, cooled and activated by high frequency low temperature low powerful Ar plasma. The peaks on glow curves are usually associated with the relaxation transitions.The analysis of glow curve profiles recorded from the investigated samples is carried out. It is found that the temperature of defreezing of cooperative segmental mobility (glass transition) is shifted to the higher temperature with drawing, the shift being more pronounced for the samples produced from decaline. It is assumed that the constrained molecular mobility in the latter may be caused by the stress in the pre-surface layers (taut tie molecules). The difference in the segmental mobility of the pre-surface layers appeared to have no influence on the short-term mechanical properties of the oriented samples produced from different solvents (tensile strength was equal to 4,7 GPa, Young modulus was equal to 180-190 GPa) but did influence on long-term properties and on the behavior upon other deformation modes, bending, in particular. The decaline-based samples with hard pre-surface layers demonstrated easy formation of multiple kink-bands being bent through 90 degrees (that effectively destroys the material) while mineral-oil based samples demonstrated the higher creep. The advantages and disadvantages of various solvents in gel-technology for producing high performance UHMWPE fibers and the routes to enhancing mechanical characteristics are discussed. The authors acknowledge the support of a research grant from the Russian Foundation of Basic Research (the project No 13-03-00634/14)
O-20 STRUCTURE OF MIXED BRUSHES MADE OF STARLIKE AND LINEAR MACROMOLECULES
A.A. Polotsky1, T.M. Birshtein2
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia and St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia
2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia and St. Petersburg State University, Physics Department, St. Petersburg, Russia
Polymer brushes - monolayers of polymer chains densely grafted onto impenetrable substrates - belong to the most popular and intensively studied polymer systems. In the last few years there exists a large interest to a new class of polymer brushes, where not the traditional linear chains but macromolecules of branched topologies, in particular, regularly branched dendrons, are grafted onto a substrate. Theoretical and computer simulation studies of dendritic brushes have revealed their nontrivial interior structure. Already the analysis of the simplest planar dendritic brush made of the first generation dendrons, or polymer stars, have shown that at moderate grafting densities the brush acquires a “two-population” structure: There is a fraction of stars that have an almost completely stretched “stem”, or root spacer, and their free arms are extended towards the solvent whereas the stars belonging to the second population are less extended and fill the space close to the grafting surface. At small grafting density only non-extended stars exist in the brush. In the present work we consider a mixed polymer brush made of starlike and linear macromolecules grafted to a solid planar substrate. The system was studied by using the Scheutjens-Fleer self-consistent field approach. Our results show that mixing of stars and chains is thermodynamically favorable with respect to lateral segregation of stars and linear macromolecules in the brush. On the other hand there is a segregation of linear and starlike macromolecules in the direction perpendicular to the grafting surface. Conformations of stars and chains in the brush are determined by the overall molecular weight and the longest path length of linear and starlike macromolecules. It is shown that short linear chains occupy the space adjacent to the grafting surface and push the stars toward the brush periphery. In the case of long chains and stars with small number of arms the interior of the brush is filled by the stars while the chains pass through the layer of the stars and expose their ends at the brush periphery. The most interesting is the intermediate situation where the chains have larger longest path but lower molecular weight than the stars. In this case, conformations of stars and linear chains depend essentially on the brush composition. When the amount of linear chains is small, they pass through the layer of stars and expose their free ends at the brush periphery. On the contrary, at large fraction of linear chains they occupy the space close the grafting plane pushing the stars to the brush periphery. Transition between two regimes occurs at intermediate brush composition and is characterized by a bimodal distribution of linear chains and large fluctuation in the position of their free ends. Such “switchable” behavior of the mixed brush suggests an idea of exploiting these brushes as molecular switches. Acknowledgement. This work is supported by the Russian Foundation for Basic Research (grant 14-03-00372-а), by the Department of Chemistry and Material Science of the Russian Academy of Sciences, and by the Government of Russian Federation (grant 074-U01).
O-21 COMPUTER SIMULATION OF POLYMER BOTTLE –BRUSHES WITH SIDE CHAINS OF DIFFERENT ARCHITECTURE
A.A. Darinskii, I.V. Michailov
Institute of Macromolecular Compounds of Russian Academy of Science, Saint-Petersburg, Russia [email protected]
Intensive computer simulations of bottle-brush macromolecules in dilute solution have been performed by the method of the Langevin’s dynamics. Bottle-brush macromolecule with the flexible backbone and densely grafted side chains with the same molecular mass (N=15) but with the different degree of branching have been considered. The coarse-grained bead-spring model has been used both for backbone and side chains. Non-bonded interactions between chain monomers corresponded to very good (athermal) or to theta solvent conditions. In all cases the interactions between side chains lead to their stretching and to the remarkable stiffening of the bottle-brush on the mesoscopic scale. In the same time the backbone remains flexible on the local scale. The effect of the branching degree of side chains on the structural characteristics of the bottle-brush has been studied. The dependence of the effective brush diameter on the branching degree of grafts agrees with the predictions of the mean field theory [1] both in the good and theta solvents. The different estimates of the induced persistence length of the backbone have been applied. As for brushes with linear side chains [2], they are not mutually consistent with each other. Nevertheless the analysis allows to conclude that at good solvent conditions the induced stiffness of the backbone is practically insensitive to the side chain architecture in agreement with theoretical predictions. In the theta solvent the backbone becomes slightly stiffer with an increase of the side chain’s branching. Literature: 1. O. V. Borisov, E. B. Zhulina, and T. M. Birshtein. ACS Macro Lett. 2012, 1, 1166−1169 2.P. E. Theodorakis, H.-P. Hsu, W. Paul, and K. Binder. J. Chem. Phys. 2011, 135,164903 This work was partially supported by the RFBR, grant 13- 03-00524, and the program № 3 of the Department of the chemistry and material science of RAS
O-22 REVERSIBLE PH-SENSITIVE HIERARCHICALLY STRUCTURED HONEYCOMB FILMS
P. Marcasuzaa1, M. Save1, P. Gerard2, L. Billon1
1 - IPREM, UMR 5254 CNRS Universite de Pau et des pays de l’Adour, Helioparc, 2 av. du President Angot, 64053 Pau Cedex, France
2 - ARKEMA, Groupement de Recherches de Lacq, RN 117, 64170 Lacq, France [email protected]
Self-organized porous polymer films, so-called Honeycomb (HC), with pores ordered into a hexagonal pattern can be elaborated by a fast evaporation method under humid atmosphere, also called “Breath Figure” approach. Moreover, self-assembly of diblock copolymers is well-known to create a nanophase separation which can be combined with the fast evaporation process to create nano-structures within the walls of the honeycomb films, leading to hierarchically structured Honeycomb films.Well-defined high molar mass PS and PMMA-based diblock copolymers were synthesized via nitroxide-mediated controlled free-radical polymerization to lead polystyrene-block-poly(4-vinylprydine) (PS-b-P4VP) and polymethacrylate-block- poly(4-vinylprydine) (PMMA-b-P4VP). One of the advantages of nanophase separation is that the first block confers the sufficient hydrophobicity required for the elaboration and stability of HC structure whereas the second block can provide an additional functional property. Here, we aim to elaborate hierarchically ordered porous film from pH-sensitive diblock copolymers able to create a sensitive inner nanostructuration. Indeed, an increase of the hydrophilicity and then of the wettability is demonstrated when pH is tuned in a large range of values which can be directly correlated to the nanostructure evolution followed by AFM in liquid cell. An in-situ transition from spherical domains to nano-rings or nano-donuts is then observed while tuning the pH and associated to a sharp variation of the wettability.
[1]. L. Billon, M. Manguian, V. Pellerin, M. Joubert, et al. , Macromolecules 2009, 42, 345. [2]. P. Escalé, M. Save, A. Lapp, L. Rubatat, L. Billon, Soft Matter 2010, 6, 3202–3210,. [3]. P. Escalé, L. Rubatat, C. Derail, M. Save, L. Billon Macro. Rapid. Comm. 2011, 32, 1072–1076. [4]. P. Escalé, L. Rubatat, L. Billon, M. Save, European Polymer Journal 2012, 48, 997-1144.
O-23 COMPLEXATION BEHAVIOR OF Co2+, Fe2+, AND Eu3+ IONS WITH 2-(1,2,3-TRIAZOL-4-YL)PYRIDINE UNITS EMBEDDED IN POLY(BUTYL METHACRYLATE) COPOLYMERS
I. Perevyazko1, G.M. Pavlov2, B. Happ1, U.S. Schubert1
1 - Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany; Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7,
07743 Jena, Germany 2 - Institute of Macromolecular Compounds, Russian Academy of Science, St. Petersburg, 199004 Russia
[email protected] www.schubert-group.com
A promising approach in today’s polymer chemistry is the conjunction of covalent linked polymer species with non-covalent interactions to establish new polymeric systems. For this purpose, supramolecular polymers containing reversible metal–ligand interactions have been widely studied.1-3 This contribution deals with a special aspect, namely crosslinked supramolecular polymers based on 2,2’-bipyridine (bpy) and the influence of the metal ion used. Poly(butyl methacrylate) copolymers embedding bidentate 2-(1,2,3-triazol-4-yl)pyridine (trzpy) chelating units as comonomer in the side chains were synthesized using the controlled radical addition-fragmentation transfer (RAFT) polymerization technique. Subsequently the macromolecules were treated with Co2+, Fe2+, and Eu3+ metal ions. The intra- and inter molecular complexation behavior of the metal ions with poly(butyl methacrylate) copolymers containing 20 mol% of trzpy units were studied in solution by macromolecular hydrodynamics methods. The sedimentation velocity of extremely diluted copolymer solutions and the dynamic viscosity of moderately diluted solutions were studied in a wide range of the salts concentrations. Net differences were observed with respect to the copolymer behavior in the presence of CoII or FeII ions on the one side and in the presence of the EuIII ions on the other side. It was found that Fe2+ and Co2+ ions could form complexes with individual ligands of the copolymer at very dilute polymer solution (c[] = 0.006), which induces the charge effects, whereas the presence of Eu3+ ions in the similar polymer solutions does not lead to the charge effects, i.e. to the complexation of ions with the ligands. This difference is caused by different numbers of coordination bonds required for complex formation. At moderate concentrations of copolymer (c[]=0.50) the increase of the divalent ion concentrations leads to the cooperative growth of the solutions dynamic viscosity more than 300 times as compared with a pure solution in acetone. Based on the rheological master curves the number of individual macromolecules forming supramolecular clusters was evaluated. 1. J.-M. Lehn, Supramolecular Chemistry, Concepts and Perspectives, Wiley-VCH, Weinheim, 1995. 2. U. S. Schubert, A. Winter and G. R. Newkome, Terpyridine-Based Materials, Wiley-VCH, Weinheim, 2011. 3. B. Happ, G. M. Pavlov, I. Perevyazko, M. D. Hager, A. Winter and U. S. Schubert, Macromol. Chem. Phys. 2012, 213, 1339-1348.
O-24 RHEOLOGY OF ASSOCIATING POLYMER SEMIDILUTE SOLUTION MODIFIED BY WORMLIKE MICELLES AT HEATING
V.S. Molchanov, V.A. Pletneva, O.E. Philippova
Lomonosov Moscow State University, Physics Department, Moscow, Russia [email protected]
Viscoelastic solutions of entangled polymer and micellar chains (wormlike micelles) of surfactant are of special interest because micellar chains enhance responsive properties of the system, whereas polymer chains make the system more stable, for instance, at heating. In particular, one could suggest that addition of polymer macromolecules can widen the range of temperatures corresponding to viscoelastic properties of these solutions, because polymer chains are not disrupted at heating like micellar chains. The aim of the research is to study the effect of temperature on the viscoelastic properties of solutions of potassium oleate (anionic surfactant) and of its mixtures with hydrophobically modified polyacrylamide (HM PAAm) at wide range of concentrations. Such polymer are able to form common network with micellar chains due to hydrophobic part of penetrate into micelles creating new cross-links as was demonstrated in our laboratory earlier. It was shown that the viscosity of semidilute solutions potassium oleate have a high values up to 400 Pas and elastic modulus up to 50 Pa at 200C. Heating of these solutions from 20 till 800С leads to the drop of viscosity by 4 orders of magnitude. At the same time the elastic modulus disappears above 450C. The values of the activation energy Еа are equal to 128±2 kJ/mol and Еа = 126±2 kJ/mol for 3 wt.% and 0.7 wt.% potassium oleate solutions, respectively. High values of Еа indicate a pronounced drop of viscosity with increasing temperature. In case of polymer/surfactant solutions behaviour of storage and loss moduli at heating is analogous to that for “pure” surfactant. But surfactant/polymer solution keeps elasticity in a wider temperature interval than “pure” surfactant solution, i.e. the network becomes more stable at heating. The viscoelasticity growths with polymer concentration (up to 1.5 wt.%) by few orders of magnitude, but, surprisingly, the activation energy of viscous flow does not decrease sufficiently and retains value close to that of micellear chains even if concentration of polymer above overlap concentration of chains in 5 times. The “pure” HM PAAm semidilute solution demonstrates small Ea 30-60 kJ/mol. Thus it can be conclude that if to add micellar chains into HM PAAm semidilute solution, than polymer/surfactant interaction is more favourable than polymer/polymer and as result the common network become sufficiently more responsive to heating likely “pure” wormlike micelles semidilute solution. The work was supported by Russian Foundation for Basic Research ofi-m 13-03-12207.
O-25 FACTORS DETERMINING MULTIVALENT BINDING OF POLYMERS: TOWARDS TUNABLE SUPERSELECTIVITY
G.V. Dubacheva1, T. Curk2, B.M. Mognetti3, R. Auzely4, D. Frenkel2, R.P. Richter5
1 - CIC biomaGUNE, San-Sebastian, Spain 2 - University of Cambridge, Cambridge, United Kingdom
3 - Universite Libre de Bruxelles, Brussels, Belgium 4 - Universite de Grenoble, Grenoble, France
5 - CIC biomaGUNE, San-Sebastian, Spain; Universite de Grenoble, Grenoble, France; Max Planck Institute for Intelligent Systems, Stuttgart, Germany
In spite of their importance for material and life sciences, multivalent interactions between polymers and surfaces remain poorly understood. Particularly, their experimental investigation is hampered by insufficient specificity (e.g. polymer/polymer interactions), poor experimental control (e.g. over binding strength between the individual ligands and receptors, or over amount of binders on nanoobjects) and poor tunability (e.g. of binder density). In this study, we have developed a well-defined, highly specific and tunable model system based on host/guest interactions. Using this experimental platform, we provided the first direct evidence for superselectivity in the multivalent binding of polymers to surfaces.1 Superselectivity means that the polymer surface density increases faster than linearly with the density of surface binding sites. Such strong dependence on surface valency allows specific targeting of surfaces displaying binding sites above a threshold surface concentration, while leaving surfaces with lower coverages unaffected. Using analytical modeling, we showed that superselectivity is indeed a consequence of multivalency and is enhanced by the ability of polymers to interpenetrate, a unique feature in comparison with other multivalent scaffolds such as particles.1 Furthermore, we systematically varied several parameters including the binding strength of individual host-guest interactions, the polymer valency and the linker connecting polymer backbone and binding sites, and studied their effect on the multivalent binding. Remarkably, we found that the quality and range of superselectivity can be precisely and widely tuned by the appropriate polymer design. This study should help to understand the regulation of multivalent polymer binding to surfaces and provide means for the rational design of polymeric drugs tailored for superselective targeting in specific bioapplications. 1Dubacheva et al, J. Am. Chem. Soc. 2014, 136, 1722.
O-26 FRACTAL GLOBULES: NEW APPROACH TO HANDMADE MOLECULAR MACHINES
S.K. Nechaev1, V.A. Avetisov2
1 - LPTMS, Orsay, France 2 - Institute of Chemical Physics, Moscow, Russia
The over-damped relaxation of elastic networks constructed by contact maps of hierarchically folded fractal (crumpled) polymer globules are investigated. It is found that the relaxation dynamics of highly anisotropic fractal globules is very similar to the behavior of biological molecular machines. Being perturbed, the system quickly relaxes to a low-dimensional manifold with a large basin of attraction and then slowly approaches the equilibrium not escaping this manifold. By these properties, synthetic fractal globules are suggested to be artificial molecular machines able to transform the perturbations into directed quasi-mechanical motion along a well-defied path. To highlight the distinctive features of a fractal globule formation and melting, an analytic description based on "intrinsic" encoding of hierarchy of crumples is proposed.
O-27 STRUCTURAL STUDIES OF IONOMER MEMBRANES MADE OF FLUOROUS COPOLYMERS BEARING PARTIALLY SULFONATED
POLYSTYRENE GRAFTS
R. Narimani1, E.M.W. Tsang2, A.C.C. Yang2, L. Rubatat3, S. Holdcroft2, B.J. Frisken1 1 - Department of Physics, Simon Fraser University BC Canada
2 - Department of Chemistry, Simon Fraser University, BC Canada 3 - IPREM/EPCP, Universite de Pau et des Pays de l’Adour, France
To investigate relationships between morphology and proton conductivity in ionic copolymer membranes, we have studied two series of fluorous copolymers bearing polystyrene grafts sulfonated from 0 to 100% (Tsang et al. 2009). Small-angle X-ray and neutron scattering experiments performed on those membranes reveal a disordered, partially phase-separated system consisting of fluorous domains in a partially sulfonated polystyrene matrix with aggregation of ion-rich domains within the matrix. The size of the fluorous domains depends on graft density, and their packing depends on the graft chain length. The spacing of the ion-rich domains is remarkably independent of either graft chain length or charge content. The impact of the morphology on the swelling and conductivity will be discussed (Narimani et al. 2013).
References E. M. W. Tsang, Z. B. Zhang, A. C. C. Yang, Z. Q. Shi, T. J. Peckham, R. Narimani, B. J. Frisken, S. Holdcroft, Macromolecules 2009, 42, 9467. R. Narimani, A. C. C. Yang, E. M. W. Tsang, L. Rubatat, S. Holdcroft, B. J. Frisken, Macromolecules 2013, 46, 9676.
O-28 HOW RIGID AND HOW FLEXIBLE CAN BE A POLYELECTROLYTE CHAIN? ANSWERS FROM HYDRODYNAMIC
STUDIES
G.M. Pavlov Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004 Russia
Polyelectrolytes play a decisive role in nature, have found wide application in industry, and have long been the focus of attention of research. Polyelectrolytes are polymers with a variable chain rigidity that is governed by the linear charge density, the ionic strength of the solution, and the structure of the monomer units. In addition, volume effects can manifest themselves in polyelectrolyte chains, whose contour length exceeds a characteristic size, i.e., the Debye–Hückel screening length (DH). Both short- and long-range interactions in chains of the same polyelectrolyte may be controlled through variation of the ionic strength of its solutions. Strong electrostatic interactions complicate investigation of the molecular and transport characteristics of such polymers. One of the basic characteristics of the conformational state of a chain in a solution is the equilibrium rigidity of a macromolecule. A measure of the equilibrium rigidity of linear macromolecules is the Kuhn segment length A or the persistence length a=A/2. The concept of the electrostatic contribution to the persistence length value was firstly developed by Odijk-Skolnick-Fixman. The modeling of the electrostatic interactions based on Debye–Hueckel approach allows to define an electrostatic persistence length of polyelectrolytes (Ael) proportional to the square of DH. Later Barrat and Joanny and Dobrynin introduced alternative models in which the electrostatic persistence length of flexible polyelectrolytes is on the order of the Debye screening length: Ael~DH. For the polyelectrolyte chains the total persistence length is a sum of bare and electrostatic terms. During investigation of polyelectrolytes, it is important to determine the ranges in which the equilibrium chain rigidity can differ with the maximum possible variations in the ionic strength of the solution. The strategy of our research was based on the following points and steps: 1) To study the polymer homologous series of charged macromolecules in a sufficiently wide range of molar masses (contour length) with the same average charge density; 2) The molar mass (M) of such series can be obtained by studying the frictional properties of the samples/fractions in solution with a sufficiently high ionic strength (typically, 0.2 M NaCl); 3) To determine the values of the intrinsic viscosity ([]) in salt-free solutions, i.e. in condition of the minimal ionic strength using the method proposed by us earlier; 4) To make judgment on the conformational status of polyelectrolyte chains in solutions of different ionic strengths using the normalized scaling plot: the dependence of ([]ML) on contour length (M/ML); 5) Quantitatively estimate the total persistence length of the chain at different ionic strengths from the intrinsic viscosity data and analyze the data, using the second step of normalized scaling plots; 6) To compare the size of linear polyelectrolyte chains with different affinity to the solvent (hydrophobic, hydrophilic) at different ionic strengths; 7) To study the polyelectrolytes with different average charge density. In this contribution will be displayed to which quantitative estimates leads the proposed approach for some polyelectrolytes with different charge density.
O-29 INFLUENCE OF IONIC STRENGTH ON FORMATION OF POLYELECTROLYTE/SURFACTANT AGGREGATES AT THE LIQUID-
GAS INTERFACE
V.V. Lyadinskaya1, A.G. Bykov2, R.A. Campbell3, I. Varga4, S.-Y. Lin1, B.A. Noskov2 1 - National Taiwan University of Science and Technology, Chemical Engineering Department, Taipei, Taiwan
2 - St.Petersburg State University, Department of Colloid Chemistry, St. Petersburg, Russia 3 - Institut Laue-Langevin, Grenoble, France
4 - Institute of Chemistry, Eotvos Lorand University, Budapest, Hungary [email protected]
Solutions of the complexes between polyelectrolytes and oppositely charged surfactants (PSC) have been intensively studied during the last two decades. The methods of the dilational surface rheology discovered strong structural changes in the surface layer of some polyelectrolyte/surfactant solutions in a narrow surfactant concentration range below the critical micellar concentation. These changes were connected with the beginning of nano- and micro-aggregate formation in the surface layer [1, 2]. The aim of this work consists in the estimation of the influence of ionic strength on the formation of polyelectrolyte/surfactants aggregates. The surface properties of PSC solutions of low ionic strength at low surfactant concentrations can change for more than one day. In this case the abrupt decrease of the surface elasticity was observed at concentrations a little less than those corresponding to the opalescence and/or phase separation in the bulk. The formation of micro- and macro-aggregates in the solution bulk takes place when surfactant concentration is close to the concentration of the charged groups of polyelectrolytes. The increase of the solution’s ionic strength results in the increase of adsorption rate due to the decrease of electrostatic adsorption barrier. This leads to strong changes of the surface dilational rheological properties and thereby of the surface layer structure at surfactant concentrations one order of magnitude lower than the concentrations corresponding to the phase separation in the bulk phase. At the concentrations close to the charge match point of the components the rheological properties are influenced by the microaggregates adsorbed from the bulk phase. In this concentration range one can observe the effects of the sample history on the rheological behavior and heterogeneity of the interface. A slight increase of the solution ionic strength gives a possibility to trace the formation of adsorption layer during the time of experiment (~ 5 hours). It was shown that the heterogeneity of the surface layer in the range of low surfactant concentrations was connected with the formation of micro-aggregates directly in the adsorption film. In this case the changes of adsorption layer structure take place at surfactant concentration only two times lower than the range of phase separation in the bulk.
1. B.A. Noskov, G. Loglio, R. Miller, Dilational surface viscoelasticity of polyelectrolyte/surfactant solutions: Formation of heterogeneous adsorption layers, Adv. Colloid Interface Sci. 168 (2011) 179
2. V.V. Lyadinskaya, A.G. Bykov, R.A. Campbell, I. Varga, S.-Y. Lin, G. Loglio, R. Miller, B.А. Noskov, Dynamic surface elasticity of mixed poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate/NaCl solutions, Colloids Surf. A (in press)
Acknowledgement The work was financially supported by the Russian Foundation of Basic Research (RFFI No. 14-03-00670_a), the National Science Counsel of Taiwan (joint project RFFI-NSC No. 12-03-92004-ННС_а) and St. Petersburg State University (project No. 12.38.241.2014)
O-30 CONONSOLVENCY IN P(S-B-NIPAM) IN DIFFERENT SOLVENT MIXTURES – A TIME-RESOLVED SANS INVESTIGATION
K. Kyriakos1, M. Philipp1, M. Dyakonova1, N. Vishnevetskaya1, C.H. Lin1, A. Miasnikova2,
A. Laschewsky3, I. Grillo4, P. Mueller-Buschbaum1, C.M. Papadakis1 1 - Fachgebiet Physik weicher Materie/Lehrstuhl fuer Funktionelle Materialien, Physik-Department, Technische
Universitaet Muenchen, James-Franck-Str. 1, 85748 Garching bei Muenchen, Germany 2 - Institut fuer Chemie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
3 - Institut fuer Chemie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany // Fraunhofer Institut fuer Angewandte Polymerforschung, Geiselbergstrasse 69, 4476 Potsdam-Golm, Germany
4 - Large Scale Structures Group, Institut Laue-Langevin, 6, rue Jules Horowitz, 38042 Grenoble, France [email protected]
The behavior of poly(N-isopropyl acrylamide) (PNIPAM) in mixtures of water and a short chain alcohol (e.g. methanol or ethanol) has attracted strong interest. Even though these alcohols are good solvents for the polymer, the cloud point (TCP) decreases upon addition of the alcohol to aqueous solutions of PNIPAM Therefore, the phenomenon has been termed cononsolvency. It has been found that, the larger the molecular volume of the alcohol, the stronger the decrease of the TCP [1]. The origin of this behavior is, however, still not fully understood. We report here on time-resolved small-angle neutron scattering (TR-SANS) experiments during temperature jumps [3] of micellar solutions of P((S-d8)11-b-NIPAM431) in heavy water (D2O), and in mixtures of D2O with 5 mole% of methanol (d-MeOH), ethanol (d-EtOH) and acetone (d-DMK) (all fully deuterated). All temperature jumps were performed from TCP – 3 K to TCP + 2 K. Figure 1 shows as an example time resolved SANS curves of the sample in D2O:d-MeOH. In all mixtures, except for D2O:d-DMK, we observe the transition from swollen micelles (red regime in Figure 1) before the TCP is reached, to collapsed micelles above the TCP, which aggregate with time to form large aggregates (blue regime in Figure 1). After a certain time (ca. 300 s), the aggregate radius cannot be resolved any longer (green regime in Figure 1), but information about the evolving aggregation is still obtained from the amplitude and the slope of the forward scattering. For the solution in D2O:d-DMK, the initial regime of swollen micelles was not observed. We observe that, the larger the alcohol molecule, the faster is the aggregation process. The stability of the colloidal dispersions is quantified using the model of colloidal dispersions of soft matter particles developed recently by Zaccone et al. [3].
Figure 1. TR-SANS curves obtained for P((S-d8)11-b-NIPAM431) in D2O:d-MeOH upon the transfer from 25 oC to 30 oC. The inset shows the temperature profile in the sample cell measured independently.
[1] Costa, R.O.R; Freitas, R.F.S. Polymer 2002, 43, 5879-5885 [2] Adelsberger, J.; Grillo, I.; Kulkarni, A.; Sharp, M.; Bivigou-Koumba, A.M.; Laschewsky, A.; Müller-Buschbaum, P.; Papadakis, C.M. Soft Matter 2013, 9, 1685-1699 [3] Zaccone, A.; Crassous, J.J.; Ballauff, M. J. Chem. Phys. 2013, 138, 104908 Funding by the DFG within the priority program “Intelligente Hydrogele” (SPP 1259) is gratefully acknowledged.
O-31 HOW THE CHEMICAL STRUCTURE INFLUENCE THE DYNAMICS OF ASSOCIATION OF AMPHIPHILIC BLOCK COPOLYMERS
E. Deniau-Lejeune1, C. Charbonneau2, O. Borisova1, C. Chassenieux2, O. Colombani2,
P. Stepanek3, O. Borisov1 1 - IPREM-EPCP, UMR 5254, Universite de Pau et des Pays de l’Adour, France
2 - IMMM-PCI, UMR 6120, Universite du Maine, France 3 - Institute of Macromolecular Chemistry, Praha, Czech Republic
When dissolved in aqueous solution most amphiphilic diblock copolymers formed “frozen” aggregates, meaning that they are not able to exchange unimers. This has often been attributed to the glassy nature of the core, as for polystyrene-b-poly(acrylic acid) (PS-b-PAA) diblock copolymers for example.1 However, with a soft hydrophobic block, such as poly(n-butyl acrylate) (PnBA) the aggregates are still frozen.2,3 A key parameter to take into account is the hydrophobicity of the hydrophobic block.4 Indeed, exchange of unimers between aggregates requires the hydrophobic block to go through the hydrophilic corona and the aqueous media. To decrease the hydrophobicity of the hydrophobic block, hydrophilic AA units were incorporated into the hydrophobic block in a controlled manner using controlled radical polymerization processes. Here we report on the structuration in aqueous solution of a series of amphiphilic diblock copolymers based on poly(n-butyl acrylate) (PnBA, hydrophobic) or polystyrene (PS, hydrophobic) and poly(acrylic acid) (PAA, hydrophilic) blocks where hydrophilic units have been incorporated in the hydrophobic block. The influence of different intrinsic parameters of the copolymers (composition, microstructure) on the dynamic properties of the aggregates formed in aqueous solution are studied as a function of pH by scattering techniques and shows that by incorporating hydrophilic units in the hydrophobic blocks the system seems to be dynamic.5, 6 The main evidence is that the size of the aggregates, i.e. hydrodynamic radius or aggregation number, depends on the pH in a fully reversible way. We will then apply the concept to prepare dynamic hydrogels from analogous amphiphilic triblock copolymers.
0
1
10
100
1000
0% 20% 40% 60% 80% 100%Ionisation degree of the AA units
Agg
rega
tion
nu
mb
er (
N ag
g)
Increasing pH
Decreasing pH
0
1
10
100
1000
0% 20% 40% 60% 80% 100%Ionisation degree of the AA units
Agg
rega
tion
nu
mb
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N ag
g)
Increasing pH
Decreasing pH
Figure 1. Reversible evolution of (Left) the aggregation number of the P(nBA50%-stat-AA50%)100-b-PAA100 and the hydrodynamic radius of the P(S-grad-AA)30-b-PAA70 (Right) (light scattering) [1] - Zhang, L.; Barlow, R. J.; Eisenberg, A.; Macromolecules 1995, 28, 6055-6066. [2] - Colombani, O. ; Ruppel, M. ; Burkhardt, M. ; Drechsler, M. ; Schumacher, M. ; Gradzielski, M. ; Schweins, R. ; Müller, A. H. E. ; Macromolecules 2007, 40, 4351-4362. [3] - M Jacquin, P. Muller, R. Talingting-Pabalan, H. Cottet, J.-F. Berret, T. Futterer, O. Théodoly, J. Colloid Interface Sci. 2007, 316, 897-911. [4] - Nicolai, T.; Colombani, O.; Chassenieux, C. Soft Matter 2010, 6, 3111-3118. [5] - Lejeune, E.; Drechsler, M.; Jestin, J.; Müller, A. H. E.; Chassenieux, C.; Colombani, O. Macromolecules 2010, 43, 2667-2671. [6] - Borisova, O.; Billon, L.; Zaremski, M.; Grassl, B.; Bakaeva, Z.; Lapp, A.; Stepanek, P.; Borisov, O. Soft Matter 2012, 8, 7649-765.
O-32 TOWARDS REVEALING THE SOLITONIC MECHANISM OF THE PHASE SEPARATION IN MULTIBLOCK POLIDISPERSE COPOLYMERS
L.I. Manevitch1, A.N. Ivanova2, Sh.A. Shaginyan1, S.I. Kuchanov3
1 - Semenov Institute of Chemical Physics of Russian Academy of Sciences, Department of polymers and composite materials, Moscow, Russia
2 - Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, Russia 3 - Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Moscow, Russia
We present the results of numerical and analytical investigation confirming our earlier hypothesis with respect to possibility of solitonic mechanism of the phase separation on the melt of multiblock polidisperse copolymer. It was shown in the paper [1], that conventional analysis of the problem in the framework of the approach elaborated in [2,3] and consisting in construction of periodic solution corresponding to microphase separation may lead to unexpected conclusion. Namely, under temperature decreasing the cloud point is attained for continuum set of the wave numbers, and one can not prefer any of them. It means that the range of the wave numbers (0,q**) exists in which all periodic structures with BCC symmetry(as well as with hexagonal or lamellar symmetries) and the wave numbers in this range have the common cloud point temperature, coinciding also with that for macrophase separation. For explanation of this unusual situation it was suggested by us that the continuum range of the wave numbers characterizes, in fact, a soliton-like profile of the copolymer structure which is a mathematical image of the new phase nucleus. To confirm this hypothesis we have found independently the spatially localized solution of the nonlinear system describing the extremals of the free energy functional in one-dimensional case. We have obtained also the analytical solution for the approximate model which is valid for incompressible system with symmetric Markov matrix under some additional assumptions. They can be formulated as conditions providing applicability of the expansion of the nonlinear constituents containing in the mentioned nonlinear system till the terms of the third order with respect to deviations of monomers density from that of the unstable melt. In the exact model the conditions of the symmetry were fulfilled and deviation from incompressible case was very small. To compare both numerical (“exact”) and analytical solutions we have found the temperature dependences of the coefficients of the obtained second order equation under fixed values of the Markov matrix elements and Flory parameters. The results of our calculations (half of the soliton profile and its Fourier spectrum) are presented below:
0 5 10 15 20 25 30 35 40 450
5
10
q=0.00569.qn-nq
2-full model
1-analitic-bin
=0.00301183,--0.0296926,=0.0460723
2
1
F(q
)
n0,0 0,2 0,4 0,6 0,8 1,0
0,35
0,40
0,45
0,50
0,55
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2-full model
1-analitic
2
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x/L
One can see a satisfactory agreement in both plots. It can be noted that the final conclusion relating to realization of solitonic mechanism may be made after investigation of two-and three-dimensional localized structures. 1. A.N. Ivanova, Sh.A. Shaginyan, S.I. Kuchanov, L.I. Manevitch. Polymer Science A 56(4), 2014. 2. S.I. Kuchanov, S.V. Panyukov. J. Polym. Sci., B. 36(6), 937, 1998. 3. A.N. Ivanova, S.I. Kuchanov, L.I. Manevitch. Journal of Math. Phys. 46, 013301, 2005. The work was supported by Program of Basic Research of the Division of Chemistry and Materials Sciences of the Russian Academy of Sciences (OKhM-3).
O-33 ELECTROPORATION OF ASYMMETRIC PHOSPHOLIPID MEMBRANES: INSIGHT FROM ATOMIC-SCALE MOLECULAR
DYNAMICS SIMULATIONS
A.A. Gurtovenko1, A.S. Lyulina2 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St.Petersburg, Russia, and Faculty of
Physics, St.Petersburg State University, St.Petersburg, Russia 2 - Institute of Physics, Nanotechnology and Telecommunications, St.Petersburg State Polytechnical University,
St.Petersburg, Russia [email protected]
In this work we employ atomic-scale molecular dynamics simulations to study electric field-induced pore formation (electroporation) in model phospholipid membranes. Since plasma membranes of animal cells are known to be asymmetric as far as the transmembrane lipid composition is concerned, here we focus on model asymmetric membranes comprised of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipid monolayers [1]. These PC and PE monolayers mimic the outer and inner leaflets of plasma membranes, respectively. Our findings provide compelling evidence that the molecular mechanism of electroporation in asymmetric lipid membranes differs considerably from that reported previously for single-component symmetric membranes. The early stages of formation of a water-filled pore are found to be asymmetric and occur mainly within the PC leaflet of the asymmetric PC/PE membrane. In other words, the PC leaflet turns out to be more prone to electric field-induced defect formation as compared to the PE leaflet: Water molecules penetrate to the membrane interior mostly from the PC side, and initial reorientation of lipid head groups also takes place in the PC leaflet. After the water pore, being partly stabilized by PC head groups, becomes relatively large, PE lipid head groups also enter the membrane interior. Such behavior is most likely due to the fact that PE lipids are capable for the formation of inter-lipid hydrogen bonds, while PC lipids are not. This results in a denser packed water-lipid interface of the PE leaflet and increases its robustness against an external electric field. Overall, our simulations clearly demonstrate that the transmembrane lipid asymmetry can be essential for understanding electroporation phenomena in living cells [1]. [1] A. A. Gurtovenko, A. S. Lyulina, Electroporation of asymmetric phospholipid membranes, J. Phys. Chem. B, submitted (2014).
O-34 PH-SENSITIVE POLYAMINO ACIDS AND NONIONIC SURFACTANT BRIJ98: HYDROPHOBICITY VS HYDROGEN BONDS
A. Bogomolova1, S.K. Filippov1, S. Keller2, H. Mackova1, M. Hruby1, P. Stepanek1
1 - Institute of Macromolecular Chemistry 2 - University of Kaiserslautern
We have studied the behavior of pH-sensitive polymers designed on the base of polymethacrylic acid. The amino acids were methacroylated to obtain polymers with polymethacrylic acid backbone and attached amino acid residues in the side chain. Three particular amino acids have been taken for this purpose: valine (P1), phenylalanine (P2) and the sequence glycine-leucine (P3). The variation in hydrophobicity of amino acid has been used to assess the impact of hydrophobicity on the behavior of the entire polymer and their interaction with a surfactant. The nonionic surfactant Brij98 was chosen for that purpose. There are two main reasons for the presence of surfactant in polymer solution; it promotes the rearrangement of a polymer molecule and the formation of stable nanoparticles below critical pH and can be used as an analog of amphiphilic drugs for future applications. Previous analysis of these systems displayed the formation of stable nanoparticles with decreasing in pH value and reversibility of the particles with pH alteration [1, 2]. We focused in our investigation on the physical processes that are in charge of nanoparticle formation. ITC (Isothermal Titration Calorimetry) and electrophoretic measurements reveal significant differences in the mechanism of interaction between the surfactant and the polymers P1 and P2 (P3). Two different models could be applied. While the polymer P2 forms hydrogen bonds with a head-group of the surfactant and makes “core-shell” structure nanoparticles, the polymer P1 with the lack of any hydrogen bonds forms pearl-necklace complexes due to the hydrophobic forces.
Acknowledgements: This work was supported by the Grant Agency of the Czech Republic (P108/12/0640) and also we gratefully acknowledge support by the Ministry of Education, Youths and Sports under grant KONTAKT LH14292. [1] Filippov, S.; Hruby, M.; Konak, C.; Mackova, H.; Spirkova, M.; Stepanek, P., Langmuir, 2008, 24, 9295-9301. [2] Filippov, S. K.; Starovoytova, L.; Konak, C.; Hruby, M.; Mackova, H.; Karlsson, G.; Stepanek, P., Langmuir, 2010, 26, 14450-14457.
O-35 SWELLING OF BLOCK COPOLYMER FILMS IN SOLVENT VAPORS
I.I. Potemkin1, A.A. Rudov1, R.A. Gumerov2
1 - Moscow State University, DWI - Leibniz Institute for Interactive Materials, Aachen 2 - Moscow State University
Using dissipative particle dynamics simulations, we study the swelling of lamellae-forming diblock copolymer films in a nonselective solvent. Both the parallel and the perpendicular orientations of lamellae in the film are studied [1]. The swelling of the film with parallel lamellae is accompanied by an increase of their number. In doing so, the lamellar thickness reveals nonmonotonous behavior: affine growth (low degree of solvent uptake) is succeeded by a decrease in thickness (high degree of solvent uptake). Whereas the first regime reflects a finite size (film thickness) effect, the decrease is a more common effect, which is also valid for perpendicular lamellae, and is due to shrinkage of the diblock copolymers due to the shielding of unfavorable AB contacts by
the solvent molecules. The film swelling leads to an increase of the number of perpendicular lamellae as well. However, such an increase is only possible if the film at first is dissolved and then condensed absorbing a certain amount of solvent. Otherwise, splitting of the lamellae requires a large-scale mass transport which is realizable neither in modeling nor in experiment. Instead of splitting, the perpendicular lamellae can tilt upon swelling. This process is much faster and satisfies the space-filling condition at the thinning of the lamellae. That is why tilted lamellae are often observed in experiments and computer simulations. We demonstrate also that the distribution of the absorbed solvent in the film is inhomogeneous with a maximum at the AB interfaces. The kinetics of the film swelling is compared with experimental data [2]. [1] Rudov, A.A.; Patyukova, E.S.; Neratova, I.V.; Khalatur, P.G.; Posselt, D.; Papadakis, C.M.; Potemkin, I.I. Macromolecules 2013, 46, 5786−5795. [2] Stenbock, A.; Rudov, A.A.; Gumerov, R.A.; Tsarkova, L.A.; Böker, A.; Möller, M.; Potemkin, I.I. ACS Macro Letters 2014 submitted.
O-36 INTER- AND MUTUAL DIFFUSION IN POLY(VINYL CHLORIDE) – COPOLYMERS OF VINYL CHLORIDE AND VINYL ACETATE*
A.A. Shcherbina, A.E. Chalykh, A.D. Aliev, M.V. Vokal
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry of RASs [email protected]
Diffusion of poly(vinyl chloride) (PVC) – random copolymers of vinyl chloride and vinyl acetate was investigated by X-ray electron probe and Scanning Electron Microscopy. Original technique of specimen preparation was developed for the first time, which allows obtaining the information of interdiffusion in different binary systems included in multi-layer composition. Interdiffusion coefficients and activation energy of copolymers diffusion were determined. The obtained results on activation energies of diffusion and mutual diffusion were compared with the literature data on gas diffusion into PVC matrix [1-3]. All these data were combined into common dependence (fig. 1). Based upon this dependence a size of “activation volume” required for “defect” migration is equal to the size of cavity required for translation mobility of krypton atom, that is 1.72 nm. Geometric estimations showed that 4-6 carbon atoms of main PVC chain are involved in formation of so size “defect”. Using Meares equation [4], where activation energy of diffusion is proportional to cohesive energy density, the length of a tube fragment, in which certain “defects” realizes single movement (jump) during its motion along a tube, was calculated. The analogous results could be obtained for the other systems: polyolefins and their copolymers, chloroprene rubbers.
Fig. 1. Comparison data on activation energies of diffusion of different substances in PVC as a function of their molecular weight. EVA – copolymer of ethylene and vinyl acetate of different composition; VC/VA – copolymer of vinyl chloride and vinyl acetate of different composition; OEAcr – oligomeric ester acrylates; DOP – dioctyl phthalate; EO-20 – epoxy oligomer; TCP - tricresyl phosphate; NR-26 – nitrile rubber.
[1] A.R. Berens // Pol. Preprints, 15 (2), p.203. [2] B.P. Tikhomirov, H.B. Hopfenberd, V. Stannett, J.L. Williams // Die Macromolecular Chemie, 118, 1968, p.171-188. [3] A.E. Chalykh, Diffusion in Polymeric Systems [in Russian], Moscow: Khimiya, 1987. 312p. [4] P. Meares // J. Am. Chem. Soc., 1954, 76 (13), p.3415–3422. * Presented work is supplied by Russian Foundation of Basic Research, Projects No. 14-03-00390
O-37 INTERACTIONS BETWEEN WATER-SOLUBLE AMPHIPHILIC POLYANIONES AND CATIONIC SURFACTANTS
I.А. Makarov, P.A. Fetin, O.N. Brevnov, I.М. Zorin, A.V. Akent’ev, A.Yu. Bilibin
St.-Petersburg State University, Department of Chemistry, St.-Petersburg, Russia, 198504, University pr., 26 [email protected]
The interaction between polymers and surfactants in solutions is a growing field of interest. Specific features of these interactions strongly depend on the polymer and surfactant types leading to different macroscopic behaviors. The case of mixed solutions of micelle forming polyelectrolytes («polysoaps») and ionic surfactants of opposite charge is more complicated due to the uncertain combination of hydrophobic and electrostatic forces. This work deals with comb-shaped micelle-forming polyanions containing carboxylic or sulfonic groups and cationic surfactants. Polymers – sodium salts of poly(11-acryloylaminoundecanoic) acid (PAAU) and poly(2-acrylamido-2-methylpropansulfonic) acid (PAMPS) – were obtained by free-radical polymerization of self-associated surface active monomers in polar solutions. Binding of cationic surfactants hexadecyltrimethylammonium bromide and 11-(acryloyloxy)undecyltrimethylammonium bromide (AUTAB) to «polysoaps» was occurred only above a surfactant concentration referred to the critical aggregation concentration (CAC) and produced polyelectrolyte-surfactant complexes (PESC). A number of methods were employed to study the interaction between polyelectrolytes and surfactants in solution, among them NMR studies, SWAXS analysis conductometry, tensiometry, potentiometry, viscometry, turbidimetry, light scattering and AFM visualization. Acryloyloxy groups in PESC were applied to fix the conformation of this supramolecular complex via polymerization. This way of preparing intermolecular complexes with stable shape is alternative compared to have been reported earlier method [1], based on intramolecular cross-linked polymerized micelles [2]. The work was made under financial support of Russian Foundation for Basic Research, grants №13-03-00474, №12-03-00746-а. NMR studies, light scattering and SWAXS analysis were carried out at St.-Petersburg State University at the Center for Magnetic Resonance, the Center for Optical and Laser Materials Research and the Center for Chemical Analysis and Materials Research respectively. 1. Zorin I.M., et al., Core Cross-Linked Polymerized Micelles and Dendronized Nanoparticles. Macromol. Symp. , 2010. 296: p. 407-415. 2. Zorin I.M., T.S. Reznichenko, A.Y. Bilibin, Polymerized micelles. Fixation of micelle structure by the core cross-linking. Polym.Bull., 2006. 57: p. 57-60.
O-38 ASSEMBLY OF BLOCK POLYELECTROLYTES WITH SURFACTANTS AND SMALL AMPHIPHILIC MOLECULES
K. Prochazka1, M. Uchman1, M. Stepanek1, P. Matejicek1, M. Gradzielski2
1 - Charles University in Prague, Department of Physical and Macromolecular Chemistry, Prague, Czech republic 2 - Technical University Berlin, Department of Physical Chemistry, Berlin, Germany
Complexes of polymers and polyelectrolytes with low-molar-mass compounds, e.g., with surfactants and other amphiphilic molecules have attracted a wide interest of scientists because of their rich and interesting behavior and a number of potential applications. Besides an important interplay of electrostatic and hydrophobic interactions, the co-assembly is driven by entropy increase due to liberation of small counter-ions in the bulk solution and changes of water structure. To design materials with required properties, a number of parameters, such as polyelectrolyte and/or surfactant chemical structure, architecture, molar mass, charge density, etc. have to be taken into account. A high number of parameters that can be varied allows one, on one hand, to tune the structure and stimuli-responsive properties of prepared nanoparticles with a high efficiency, but on the other hand, it requires complex and lengthy studies of potentially applicable systems. We have recently studied complexes of poly(methacrylic acid)-b-poly(ethylene oxide), PMA-PEO, with (i) N-dodecylpyridinium chloride and (ii) [3-cobalt(III) bis(1,2-dicarbollide)]- anion "COSAN" by a combination of static and dynamic light scattering, small angle neutron and X-ray scattering, NMR, microscopy (AFM and cryo-TEM), ITC and other techniques. The studies of the co-assembly of PMA-PEO with very high molar mass in a broad range of molar ratios of the surfactant - copolymer, Z, allowed us to identify four different regimes of the self-assembling behavior: (i) coexistence of loose aggregates of electrostatically bound surfactants to PMA block with free and almost unperturbed copolymer coils for Z 1; (ii) formation of aggregates with ill-defined cores formed by DPCl micelles attached to coiled PMA chains (beads-on-a-string nanoparticles) in the range 0.38 Z 1 (they coexist either with free copolymer chains and swollen nanoparticles decorated by surfactant micelles - for lower Z, or with core-shell nanoparticles - for higher Z); (iii) formation of compact core-shell particles with cores formed by ordered (crystalline) DPCl micelles for 1 Z 3.6 and (iv) the coexistence region of core-shell nanoparticles with free DPCl micelles. The PMA-PEO co-assembly with COSAN surprisingly yields nanoparticles containing insoluble cores formed by PEO-COSAN complex (stabilized, e.g., by interesting dihydrogen bonds) and soluble PMA shells. Since boron-containing compounds find application in medicine, e.g., as "boron neutron capture therapy" agents and COSAN-based compounds have been recently discovered as potent inhibitors of HIV protease, the nanoparticles have been studied as promising drug carriers.
O-39 THE SELF-ASSEMBLY OF THE STAR-LIKE POLY(2-ISOPROPYL-2-OXAZOLINE) IN AQUEOUS SOLUTIONS
A.I. Amirova, M.M. Dudkina, A.V. Tenkovtsev, A.P. Filippov
Institute of Macromolecular Compounds of Russian Academy of Sciences, St. Petersburg, Russia [email protected]
One of the especial properties of poly(2-isopropyl-2-oxazoline) (PiPrOx) is the lower critical solution temperature (LCST) close to the human body temperature. It is a reason why this thermosensitive polymer has been studied last years intensively. While most of the papers are devoted to linear PiPrOx, the influence of copolymer structure and terminal groups, we investigated the star-like PiPrOx with 8 arms and octa-tert-butylcalix[8]arene core. The synthesis of polymer under study was described in detail previously [1]. The aim of present work was to obtain the data concerning the molecular and hydrodynamic characteristics of PiPrOx and self-assembly of it macromolecules as function of a temperature. To obtain the molar-mass and hydrodynamic parameters, the sample was characterized by molecular hydrodynamic and optic methods in solutions in ethanol and chloroform. The molar mass is equal to about 20000, i.e. the arm length is 8 nm. The hydrodynamic radius of individual star macromolecules is 4.0 nm. LCST 25°C was determined using a temperature dependence of transmission for water solutions. The self-assembly of PiPrOx macromolecules in the aqueous solutions within concentration range 0.2 - 3.2 g/dl was investigated by the static and dynamic light scattering methods at temperatures from room to 52°C. The scattering intensity, hydrodynamic radius values, and composition of scattering objects were measured and their temperature and concentration dependences are discussed. The aggregation of star-like PiPrOx macromolecules in water was observed at room temperature even. The temperature increasing leads to the growth their fraction in solutions because macromolecules form new aggregates. It is needed to note that size of supramolecular structures does not depend on temperature at this heating stage. At high temperature, there were just aggregates in solution and their dimension grew with temperature. At each step, consequently, the number of macromolecules forming the aggregates increased. The growth of aggregate hydrodynamic radii was fixed with a dilution. 1. A.V. Ten’kovtsev, A.E. Trofimov, L.I. Shcherbinskaya, Polym. Sci. Ser. B 2012, 54, 142.
O-40 MONTE CARLO COMPUTER SIMULATION OF A SINGLE FLEXIBLE-SEMIFLEXIBLE COPOLYMER CHAIN: DIAGRAM OF
STATES AND ANALYSIS OF KNOTS
V.A. Ivanov1, J.A. Martemyanova1, W. Paul2, P. Virnau3, F. Schmid3 1 - Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
2 - Institute of Physics, Martin-Luther-University Halle-Wittenberg, 06099 Halle (Saale), Germany 3 - Institute of Physics, Johannes-Gutenberg-University of Mainz, 55099 Mainz, Germany
A single copolymer chain consisting of flexible (F) and semiflexible (S) blocks has been studied by means of Monte Carlo computer simulation using the bond fluctuation model [1] and Wang-Landau sampling [2]. Blocks F and S have the same parameters of volume interaction, i.e. in the sense of volume interactions it is a homopolymer chain. Regular sequence and 1:1 composition of blocks F and S has been used. Parameters of the model are the stiffness parameter of semiflexible block and the block length. Chain length was equal to N=256. Diagram of states has been obtained and compared with that for the smaller chain length N=64. We have found that globular conformations can have different structures: (1) the core composed of semiflexible blocks and the shell composed of flexible blocks; (2) the core composed of flexible blocks and the shell composed of semiflexible blocks. For high values of stiffness these structures transform to dumbbell-like globule (core has the shape of a cylinder) and saturn-like globule (shell has the shape of a torus), respectively. The structure (1) or dumbbell globule is formed for smaller values of the length of blocks while the structure (2) or saturn-like globule is formed for larger block lengths. The coil-globule transition can occur either in one stage or in two stages (i.e., with possible intermediate states) depending on the stiffness of S-blocks and on the block length. Additionally, we have performed the analysis of knots in globular structures. We have found that saturn-like conformations are highly knotted (knotting probability is about 80%) whereas the dumbbell conformations are mostly unknotted (knotting probability is about 8-14%). The financial support from DFG (project PA 473/10-1) and RFBR (grant 13-03-91334-NNIO-a) is highly appreciated. Computer simulations have been performed at the Supercomputing Center of Lomonosov Moscow State University. References: [1] Carmesin I., Kremer K., Macromolecules, v.21, p.2819 (1988); Deutsch H.-P., Binder K., J. Chem. Phys., v.94, p.2294 (1991); Paul W., Binder K., Heerman D.W., Kremer K., J. Chem. Phys., v.95, p.7726 (1991). [2] Wang F., Landau D.P., Phys. Rev. Lett., v.86, p.2050 (2001); Wang F., Landau D.P., Phys. Rev. E, v.64, p.056101 (2001).
O-41 ADSORPTION KINETICS OF PROTEINS AND PROTEIN/SURFACTANT COMPLEXES AT THE GAS – LIQUID
INTERFACE
B.A. Noskov, A.A. Mikhailovskaya St.Petersburg State University, St.Petersburg, Russia
The protein adsorption mechanism at liquid – fluid interfaces is a complicated subject because of the different nature of forces in operation and numerous factors influencing the adsorption process. A possible experimental approach to study the protein adsorption kinetics consists in the modification of protein molecules in order to distinguish a special kind of interactions among other ones in operation for unmodified proteins. Some authors used different chemical modifications of the proteins to elucidate the influence of some special interactions1. In this work the charge of a protein globule was changed at the expense of the physical interactions between the globule and ionic surfactants. The kinetic dependencies of the dynamic surface elasticity indicate that the protein tertiary structure is preserved in a broad concentration range. The kinetic dependencies of the adsorbed amount were measured by the ellipsometry. A simple model based on the Smoluchovski equation was developed to describe the adsorption kinetics of the complexes between globular proteins and ionic surfactants at the gas-liquid interface. The results of calculations were compared with the data of ellipsometric measurements for solutions of the complexes between bovine serum albumin and sodium dodecylsulfate. The charge of the complex was the only fitting parameter. The obtained values of the charge were much less than those calculated from the dissociation constant of amino groups but agreed with the data2 obtained from the electrophoretic mobility thereby indicating the counter ion condensation on the surface of the globule. These results confirm the conclusions from the measurements of kinetic dependencies of the dilational surface elasticity3. Literature:
1. Peter Wierenga, Marcel Meinders, Maarten Egmond, Alphons Voragen, Harmen de Jong. 2005. Qualitative Description of the Relation between Protein Net Charge and Protein Adsorption to Air – Water Interface. J. Phys. Chem. B 109, 16946-16952.
2. Barbara Jachimska, Monika Wasilewska, Zbigniew Adamczyk. Characterization of Globular Protein Solutions by Dynamic Light Scattering, Electrophoretic Mobility, and Viscosity Measurements. 2008. Langmuir 24, 6866-6872.
3. Alesya Mikhailovskaya, Boris Noskov, Shi-Yow Lin, Giuseppe Loglio, Reinhard Miller. 2011. Formation of Protein/Surfactant Adsorption Layer at the Air/Water Interface as Studied by Dilational Surface Rheology. J. Phys. Chem. B 115, 9971-9979.
Acknowledgement: The financial support from the Russian Foundation of Basic Research (RFFI No. 14-03-00670_a) is gratefully acknowledged.
O-42 QUANTITATIVE CRITERIA FOR THE COMPARATIVE SIZE OF THE NANOPARTICLES
T.Kh. Rakhimov
National University of Uzbekistan named M.Ulugbek, Tashkent, Uzbekistan Republic [email protected]
The key characteristic of nanoparticles that determines as the objects belonging to this category is their size. In terms of chemical characteristics such catalytic activity the most important attribute is the surface area. Accordingly, a comparison with the use of nano-objects is expedient on a base of quantitative statistical characteristics reflecting the average values of the active surface. In this paper we introduce two such characteristics: the rms diameter and polydispersity index of nanoparticles. They can serve as a link between the nanocomplexes synthesis issues and optimization of their properties. The values of these characteristics can be determined from experimental data - for example, micrographs obtained using electron microscopy. Statistical analysis used the method of small samples, limited to n ≈ 40. For comparison, the nanoparticles used squares sense radii or diameters of the particles, whereas the contribution of particles with a large diameter is greater than the smaller. For the calculations can be considered a form of nanoparticles close to spherical or ellipsoidal. The particle diameter is not considered in depth, i.e. virtually equal to the rm, defined by two coordinates. Rms diameter of a single particle in
this case will be equal 2
22
DDD yx
i
. For example, if the dimensions are 10 nm and 6 nm,
vertical, horizontal, the rms diameter of one particle is equal to the square root of (100 +36 ) / 2 = 68, that is 8.25, but not 8 . Particles whose shape farther from spherical, have thus increasing the mean diameter. Rms diameter calculated as the square of the sum of squares of the diameters of all particles divided by the number of particles
nn
т
i
yixiт
ii
DDD
D
1
22
1
2
2,
where n - the number of nanoparticles. As you can see from the example, the average size of the arithmetic mean exceeds 11 nm. Polydispersity index L - introduced in this paper a dimensionless
quantity , giving a semi-quantitative characterization of nanoparticles formed uneven sizes. Calculated by the formula
2
2
1
D
DDn
ii
L
.
Polydispersity index equal to zero with equal spherical particles . Its physical meaning that it defines the surface area to spread the nanoparticles. For the above example, L = 51 %.
Dx Dy Dx2 Dy
2 Davg In the amount of 438
4 6 16 36 5.10 Per one particle 146
10 12 100 144 11.05 rms diameter 12.1
16 18 256 324 17.03
O-43 MECHANICAL STRETCHING OF A SINGLE PROTEIN MACROMOLECULE
E.Z. Meilikhov, R.M. Farzetdinova
Kurchatov Institute, Moscow, Russia [email protected]
Recently the methods to investigate single protein molecule stretching have been developed. In experiments, the external force is applied between a pair of “opposite” amino-acid residues and the dependence of the distance x between them is measured as a function of the force. Dependencies of a single protein molecule extension on the applied force demonstrate some “fine structure”, but all of them have some general feature: when the force becomes strong enough the protein begins to “flow”, that is to lengthen rapidly without further growth of the applied force. It seems as though the sharp (phase?) transition occurs under which the protein “skeleton” loses the stability and transits from the elastic state into the plastic one. We are aimed to describe analytically the process of protein mechanical stretching. To this end, we investigate the hypothetic protein phase transition in terms of mean-field theory which, putting aside the nature of interacting elements composing the protein network, describes general features of such systems, estimates qualitatively their stability, etc. We have studied the phase transition of a protein macromolecule from the elastic state to the plastic one, which arises from mechanical stretching. Near that transition, the rigidity falls according to the percolation theory. The relevant critical force depends significantly on the average number of bonds for amino-acid residues in a protein. Protein networks with average coordination number smaller than some critical value could not exist in the globular state arbitrarily small force destroys that state. In a whole, results agree with experiments, and that gives promise that the effective field theory describes adequately integral mechanical properties of protein macromolecules.
O-44 BOND ORIENTATION PROPERTIES IN LIPID MOLECULES OF MEMBRANES (MOLECULAR DYNAMICS SIMULATIONS)
A.L. Rabinovich1, A.P. Lyubartsev2
1 - Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, Petrozavodsk, Russia 2 - Division of Physical Chemistry, Department of Material and Environmental Chemistry, Stockholm University,
Sweden [email protected]
Rapid development of computer power during the last decade has made molecular simulations of lipid membranes feasible for many research groups, which, together with the growing general interest in investigations of these very important biological systems has lead to tremendous increase of the number of research on the computational modeling of lipid membranes [A.L. Rabinovich, A.P. Lyubartsev, Polymer Science. Ser.C. 2013. V.55. No.1. P.162-180]. Natural membranes are very complex heterogeneous systems consisting of many different molecules which are involved in a variety of cellular processes. The polyunsaturated lipid chains are of great importance in structure and functioning of natural membranes. At the same time, full understanding of the effects of lipid unsaturation on various physical properties of membranes at the molecular level, affecting their functioning, is not yet achieved. An understanding of the molecular basis of various physical properties of lipids allows one to narrow down the list of hypotheses under consideration about the possible functions of various components such as acyl chains in lipid membranes, e.g., the maintenance of proper bilayer fluidity and permeability, of the activity of membrane-bound enzymes, etc. Atomistic molecular dynamics simulations have been carried out for 16 different fully hydrated phosphatidylcholine bilayers, having 16 or 18 carbon atoms in fully saturated sn−1 chain and from 18 to 22 carbon atoms in sn−2 chain with different degree of unsaturation, with the purpose to investigate the effect of unsaturation on physical properties of lipid bilayers. The simulation boxes were filled by 64 lipid molecules per monolayer and 30 water molecules per lipid. The two hydrocarbon tails, the glycerol section and the head group of the lipid molecules were treated in accordance with their known chemical structure. All hydrogen atoms were explicitly included in the computations. The 16 unsaturated pure bilayer systems were coupled to an external temperature bath of 303 K and a pressure bath of 1 atm. 100 ns trajectories were calculated (after 20 ns relaxation trajectories the MD production runs of 80 ns were executed) for all bilayer systems. Different equilibrium structural and dynamic properties of the bilayers were defined, such as profiles of C-C and C-H bond order parameters of lipid molecules with respect to the bilayer normal, the orientational fluctuations of these bond vectors (probability density distributions of C-C and C-H bond orientations), the root mean square values of the positional fluctuations of all lipid atoms relative to the average atomic coordinates, etc. It was shown that the study of anisotropy degree of bond orientations probability distributions allows distinguishing extended regions with different types of angular fluctuations of bonds in a membrane formed by lipid molecules with unsaturated chains. Thus, besides of computations of the conventional ”order parameter” we suggested to characterize the bonds according to a newly introduced ”anisotropy coefficient” computed from the angular distributions between the bond and the bilayer normal. We have demonstrated that such an analysis allows one to get deeper insight into ordering and orientational behaviour of various bonds and to separate these two effects. The computed properties were compared with available experimental data and discussed in relation to their possible role in the biological functioning of membranes. This work has been supported by grants Nos. 1642.2012.4, 1410.2014.4 for leading research schools of Russian Federation; and the European Union FP7 grant No. 310465 MembraneNanoPart.
O-45 DILATIONAL SURFACE ELASTICITY OF SPREAD MONOLAYERS OF POLYSTYRENE MICROPARTICLES
A.G. Bykov1, G. Loglio2, R. Miller3, B.A. Noskov1
1 - St. Petersburg State University, St. Petersburg, Russia 2 - UniversitadegliStudi di Firenze, Firenze, Italy
3 - MPI fur Kolloid und Grenzflachenforschung, Golm, Germany [email protected]
Properties of spread and adsorbed layers of solid particles at liquid/fluid interfaces are attracting increasing attention nowadays due to the ability of the particles to stabilize foams and emulsions [1]. Recently the key role of dilational and shear rheological properties of particle monolayers in the stability and dynamics of the corresponding disperse systems has been emphasized. In this work we investigated the dynamic dilational surface elasticity of the monolayers of charged polystyrene (PS) particles with the diameter of 1 µm at the air/water interface. The formation of ordered structure of PS microparticles even at low surface coverages due to the long range electrostatic repulsion was observed by the optical methods. The real part of the surface elasticity for this structure is about 50 mN/m. The dilational surface elasticity increases by one order magnitude up to 550 mN/m with the increase of particle concentration and formation of the closed packed structure. The further increase of the surface coverage results in the monolayer collapse and the surface elasticity drops to zero. The ratio between the real and imaginary parts decreases from ten to about two at the increase of the oscillation frequency from 0.01 to 0.1 Hz at surface pressure below the collapse. Thus the behavior of the monolayer changes from pure elastic to viscoelstic at the increase of frequency. We assume that this transition can be induced by the reversible formation of aggregates. In this case the imaginary part of the surface elasticity increases, when the rate of aggregates formation becomes comparable with the rate of deformation. Recently the similar aggregate formation was observed for spread films of HFBII hydrophobin, which is characterized by the quite ‘sticky’ and hydrophobic globules [2]. Acknowledgement: The work was financially supported by the RFFI (No. 14-03-00670_a), joint project RFFI-NSC (No. 12-03-92004-ННС_а) and St. Petersburg State University (project No. 12.38.241.2014)
1. P. A. Yazhgur, B. A. Noskov, L. Liggieri, S.-Y. Lin, G. Loglio, R. Miller and F. Ravera Soft Matter, 2013, 9, 3305–3314 Dynamic properties of mixed nanoparticle/surfactant adsorption layers
2. N. A. Alexandrov, K. G. Marinova, T. D. Gurkov, K. D. Danov, P. A. Kralchevsky, S. D. Stoyanov, T. B.J. Blijdenstein, L. N. Arnaudov, E. G. Pelan, A. Lips Journal of Colloid and Interface Science 376 (2012) 296–306 Interfacial layers from the protein HFBII hydrophobin: Dynamic surface tension, dilatational elasticity and relaxation times
O-46 TETRAPYRROLIC FLUORESCENT MOLECULAR ROTOR CONJUGATES WITH POLYIMIDE BRUSHES AS THE NEW TYPE OF
PHOTODYNAMIC THERAPY AGENTS
L.G. Klapshina1, I.V. Balalaeva2, I.S. Grigoriev1, M.A. Izquierdo3, S.A. Lermontova1, N.Yu. Shilyagina2, M.V. Shirmanova2, T.K. Meleshko4, D.M. Ilgach4, A.V. Yakimansky4,
M.K. Kuimova3 1 - G.A.Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Tropinin str. 49, GSP-445,
603600 Nizhny Novgorod, Russia 2 - Lobachevsky State University of Nizhnii Novgorod, Institute of Living Systems, Gagarin pr. 23, 603950 Nizhny
Novgorod, Russia 3 - Chemistry Department, Imperial College London, Exhibition Road, London SW7 2AZ, UK
4 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, 199004 St. Petersburg, Russia
Novel porphyrazine fluorescent molecular rotors i.e. molecules in which the non-radiative decay of the fluorescent excited state is strongly influenced by the viscosity of surrounding medium are developed. In addition, these porphyrazines show a unique (for this class of the compounds) combination of molecular rotor properties with high photodynamic activity. This allows, in principle, to perform the real time fluorescent monitoring of photoinduced cell death since it is known that the intracellular viscosity gradually increases during the PDT process [(M.Kuimova et al, Nature Chemistry, 2009, 1, 69].
Fig.1. Intracellular localization of the porphyrazine photosensitizer incorporated into the polymer brush nanoparticles 1 – nucleus, 2 – nuclear membrane
Fig.2. Whole-body fluorescence imaging (a-before, b- 3 h after nanoparticle aqueous solution injection, tumor within the circle line)
The conjugation of porphyrazines with regular polyimide brushes, containing polymethacrylic acid side chains, gives water soluble biocompatible nanoparticles, possessing a bright red emission in 630-670 nm region. The time-resolved spectroscopy experiments revealed photoinduced singlet oxygen generation in porphyrazine/polyimide brush conjugate aqueous solution. In the cell culture experiments the nanoparticles were shown to be internalized and accumulated in the tumor cells on the nuclear membrane and nucleus. The accumulation of the photosensitizer in nuclear and perinuclear regions has a very significant value in photodynamic therapy, because nuclear membranes are most vulnerable to photodamage. Cell investigations confirmed a high photodynamic activity of the nanoparticles. Whole-body fluorescent imaging experiments on mice bearing metastatic colorectal carcinoma showed the selective nanoparticle accumulation in a model tumor. This work was supported by the RFBR (grants 13-04-40228-H, 14-02-00753_a, 14-03-31809-mol-а, 14-03-31130 _mol_ a, 13-04-92612_KO), Ministry of Education and Science of RF(Contract 14.Z50.31.0022)
2
21
1
O-47 DYNAMIC AND STATIC LIGHT SCATTERING OF THE COLLOIDS OF GOLD NANOPARTICLE ENSEMBLES CAPPED BY KAPPA-
CARRAGEENAN
E.R. Gasilova1, M.V. Lesnichaya2, G.P. Aleksandrova2, B.G. Sukhov2 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St._Petersburg, Russia
2 - A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia [email protected]
The interest in nanosized crystals of gold arises mainly due to their localized surface plasmon resonance that is responsible for dramatic light adsorption and resonantly enhanced scattering of gold nanoparticles (GNPs). GNPs are used in biolabeling, biosensing, drug delivery, and anti-cancer therapy. Colloidal GNPs are often produced nowadays by eco-friendly one-pot synthesis using biomacromolecules as both reducing and capping agents. The combination of photophysical properties of GNPs with therapeutical properties of both components (GNP and biomacromolecule) leads to efficient theranostic applications of the bionanocomposites [1]. As the aggregates of closely spaced GNPs generate higher signal enhancement than the sum of individual nanoparticles [2], ensembles of gold nanoparticles (GNPE) are used in the most part of GNP applications [3]. Assembly of GNPs can be created during the one-pot synthesis by templating GNPs within large biomacromolecules. DNA-based GNPE are studied most of all [4]. Water-soluble polysaccharides as templates for GNPE are less examined. In the current work, we focused on colloidal GNPE formed within kappa-carrageenan (-CGN) aggregates. Kappa-carrageenan is a promising candidate for producing large GNPE because -CGN easily aggregates due to long-living intermolecular contacts of -CGN's helices [5]. Recently, nanobiocomposites of -CGN with silver nanoparticles were synthesized [6]. The same approach was used for the synthesis of the studied -CGN/GNP composite containing 4.2 w/w% of gold. Transmission electron microphotography reveals single spherical GNPs of 10 nm diameter as well as several ensembles of closely spaced GNPs. In the current work, we studied the dynamic and static light scattering of very dilute aqueous solutions of -CGN/GNP composite. We determined the hydrodynamic radius of colloidal aggregates (Rh = 150 10 nm), and the colloidal radius of gyration (Rg = 89 6 nm). The magnitude of the structure-sensitive ratio Rg/Rh = 0.59 indicates that the mass distribution within -CGN/GNP colloid is non-uniform (the colloidal core is more dense than the shell). The further insight into the internal structure of the colloids was obtained by studying the dependences of Rg and Rh on the factors affecting the -CGN aggregation through the helixcoil transition of -CGN. In particular, heating is known to induce the helixcoil transition of -CGN, whereas addition of KCl induces the opposite coilhelix transition. Although NaCl does not have any impact on the helixcoil transition of -CGN, the shielding of the charge of SO3
– groups of -CGN by Na+ ions can change the colloidal radius. Thus, we report the influence of temperature, KCl, and NaCl on Rg and Rh of the colloidal aggregates of -CGN/GNP composites. Financial support of Russian Foundation for Basic Research (grant 14-03-00859_a), and SB RAS (interdisciplinary integration project 134) is gratefully acknowledged.
[1] G. Doria, et al., Sensors 2012, 12, 1657. [2] Sh. Xu, et al., Langmuir 2008, 24, 7492. [3] S. Pierrat, et al., Nano Lett. 2007, 7, 259. [4] C.A. Mirkin, et al., Nature 1996, 382, 607. [5] V.L.Campo, et al., Carbohydrate Polymers 2009, 77, 167. [6] M.V. Lesnichaya, et al., Russian Chemical Bulletin, 2010, N 12, 2266.
O-48 LAYER BY LAYER ASSEMBLY BASED ON POLYIMIDE BRUSHES: PLANAR FILMS AND MICROCAPSULES CONTAINING MAGNETITE
NANOPARTICLES
M.V. Lomova1, D.M. Ilgach2, S.V. German1, T.K. Meleshko2, I.V. Malyar1, N.N. Bogorad2, O.A. Inozemtseva1, A.M. Pavlov3, M.N. Antipina4, A.V. Yakimansky2, G.B. Sukhorukov3,
D.A. Gorin1 1 - Saratov State University,Saratov, Russia
2 - Institute of macromolecular compounds RAS, Saint-Petersburg, Russia 3 - Queen Mary University of London, London, UK
4 - Institute of Materials Research and Engineering, Singapore, Singapore [email protected]
Encapsulation is usually applied when protected delivery of sensitive species is needed. Versatile carriers of nano- and micrometer scale can be built up by well established Layer-by-Layer (LbL) technique.1 Capsule shells are commonly formed via assembling of alternating polyanionic and polycationic layers and/or charged nanoparticles onto the surface of solid core microparticles followed by dissolution of the cores. Polymer multilayers, successful encapsulation of water-soluble relatively low molecular weight substances was reported, for instance, by means of solvent evaporation/extraction and via surface cross-linking of microcapsule polymer shells.2 However, new measures to prevent diffusion of low molecular weight compounds through the polymer multilayer network have to be sought in order to extend the application area for the polymer multilayer microcapsules. Lvov et al. demonstrated LbL assembly of polystyrene sulfonate and polyallylamine hydrochloride in formamide medium assembling shells of nanometer thickness.3 In this work, we report on the synthesis of ethanol-soluble brush-polymers and their use as constituents for assembly of polymer multilayer films and microcapsules. Magnetite nanoparticles were obtained by the co-precipitation technique. Polymer layers built-up with the use of ethanol-soluble polyimide brushes (polyanion) and polyethelenimine (polycation) were constructed in the medium of ethanol. To sensitize the obtained planar films and capsules to magnetic field, their multilayers were functionalized by magnetite nanoparticles, dispersed in aqueous medium. Microcapsules assembled on calcium carbonate core template with shells, containing magnetite nanoparticles and ethanol-soluble polyimide brushes with polymethacrylic acid side chains, were composed by layer-by-layer technique in non-aqueous conditions, being favorable for a challenging problem of encapsulation of water-soluble compounds, in particular, drugs with low molecular weight. A possibility to move the prepared microcapsules with magnetite nanoparticles in the shells by magnetic field is shown. Microcapsules were characterized by optical microscopy, atomic force microscopy and scanning electron microscopy. It is shown that the use of the investigated brush-like polyanions, instead of linear ones, makes it possible to increase the shell thickness gain per ionic assembling cycle by a factor of ~3. This type of microcapsules is prospective for the encapsulation of low molecular weight compounds and decreasing of layer numbers required for stable microcapsule shell. The reported study was partially supported by RFBR (grant 12-03-33088 mol_a_ved, Government of the Russian Federation (grant №14.Z50.31.0004). The authors are grateful to Dipl. Eng. Marietta Böhm (Chair of Macromolecular Chemistry 2, University of Bayreuth, Germany) for SEC measurements. [1] E. Donath, G. B. Sukhorukov, F. Caruso, S. A. Davis, H. Möhwald, Angew. Chem. Int. Ed. 1998, 37, 2202. [2] J. Bai, S. Beyer, S. Y. Toh, D. Trau, ACS Appl. Mater. Interfaces 2011, 3, 1665. [3] V. K. Kamineni, Y. M. Lvov, T. A. Dobbins, Langmuir 2007, 23, 7423.
O-49 MICROSPHERES COATED WITH POLYMER/ASTRALEN LAYERS AND SILVER NANOPARTICLES USED AS SERS PLATFORM
I.Y. Stetciura1, A.V. Markin1, A.N. Ponomarev2, A.V. Yakimansky3, T.S. Demina4, C. Grandfils5,
D.V. Volodkin6, D.A. Gorin1 1 - Saratov State University
2 - Science & Technical Center of Applied Researches 3 - Institute of Macromolecular Compounds RAS
4 - Enikolopov Institute of Synthetic Polymer Materials 5 - University of Liege-Institute of Chemistry
6 - Fraunhofer Institute for Biomedical Engineering [email protected]
Surface enhancement Raman scattering (SERS) is widely used for the label-free, non-contact, and non-destructive detection of biologically active molecules.1 SERS allows obtaining important information about chemical composition of complex biological objects, such as cells and tissues.2 Progress in SERS application in medicine and biology is associated with synthesis and optical characterization of new nanostructured materials for development of SERS platforms.3 Generally SERS platforms4 are created by using silver5 and gold6 nanoparticles as enhancers. Here we prepared a new type of micrometer-sized SERS substrate – core-shell microparticles composed of solid carbonate core coated with nanoparticles of astralen7 and silver8 . Astralen has been assembled with polyallylamine hydrochloride (PAH) by the layer-by-layer assembly followed by Ag nanoparticle formation by means of mirror reaction giving a final structure of the composite particle CaCO3(PAH/astralen)x/Ag, where x=1-3. The components of the microparticle bring multiple functionalities: i) easy identification by Raman imaging (photostable astralen) and ii) SERS due to rough surface of Ag nanoparticles. A combination of Ag and astralen nanoparticles gives enhancement of astralen Raman signal more than one order of magnitude. The microspheres are effective SERS substrates, they are stable at physiological conditions and can be easily detected by enhanced Raman signal of astralen as well as by optical microscopy. Raman signal of commonly used scaffold substances such as polylactide and polyvinyl alcohol as well as extracellular matrix (ECM) component (hyaluronic acid) are significantly enhanced. SERS signal was obtained at power of below 1 mW that is in the range used for biological samples. Finally, the microspheres are shown to be promising SERS platform to probe in a real time development of ECM and state of a scaffold. It is also interesting to stress that silver aggregates play the role of "heat receivers", thanks to their low thermal capacity, and as consequence their faster heating capacity in comparison with a carbon covering. It should be therefore expected that heat would be uniformly and effectively dissipated on surface homogenously covered by astralen while avoiding local heating. The last effect has good prospects for a laser hyperthermia. Thus, we demonstrate that new mechanically robust and easily detectable (by astralen signal or optically) core-shell microspheres based on biocompatible CaCO3 can be used as SERS platform8. Particle design opens many future perspectives for fabrication of SERS platforms with multiple functions for biomedical applications, for example for theranostic. The reported study was partially supported by RFBR (grant 12-03-33088 mol_a_ved, Government of the Russian Federation (grant №14.Z50.31.0004). D.V.V. acknowledge the Alexander von Humboldt Foundation. I.Y.S thanks DAAD(A/12/86694).
1. K. Kneipp, Physics Today 2007, 60, 40–46. 2. C. Krafft, B. Dietzek, J. Popp, Analyst 2009, 134 (6), 1046-1057. 3. S. Abalde-Cela, P. Aldeanueva-Potel, C. Mateo-Mateo, et.al. J. Royal Soc. Interface 2010,
7, 435-450. 4. R. A. Tripp, R. A. Dluhy, Y. Zhao, Nano Today 2008, 3 (3–4), 31-37. 5. C. S. Seney, B. M. Gutzman, R. H. Goddard, J. Phys. Chem. C 2008, 113 (1), 74-80. 6. N. Pazos-Perez, W. Ni, A. Schweikart, et.al. Chemical Science 2010, 1 (2), 174-178. 7. A. I. Shames, I. Felner, V. Yu. Osipov, et.al. Nanosci. Nanotechnol. Lett. 2011, 3, 41–48. 8. I.Y. Stetciura, A.V. Markin, A.N. Ponomarev, et.al. Langmuir 2013, 29 (12), pp 4140–4147.
O-50 ELECTRON MICROSCOPY AND X-RAY ANALYSIS OF NANOCOMPOSITES BACTERIAL CELLULOSE/HYDROXYAPATITE
V.V. Klechkovskaya1, N.A. Arkharova1, A.V. Severin2, U.G. Baklagina3, A.K. Khripunov3
1 - Institute of Crystallography RAS, 119333, Leninskii pr.59, Moscow, Russia 2 - Dept. of Chemistry Moscow State University, 119991, Leninskie gory, Moscow, Russia
3 - Institute of macromolecular compounds RAS, 199004, Saint-Petersburg, Bolshoy pr. 31, Russia [email protected]
Organo-inorganic composite materials have recently attracted a great deal of attention for its similarity to the natural bone. As an organic component are usually used different polymers such as collagen, chitin, chitosan, bacterial cellulose (BC), polyamide, polyethylene etc. Among the other natural polymers BC has a property set (high hydrophilicity, moldability, water absorbance, porosity, mechanical strength, biocompatibility), which makes it an extremely promising material for bone engineering. Nanosized hydroxyapatite (HAP) is the main part of mineral in bone tissue and so is more perspective material as an inorganic component. However, structure and properties of such biocomposites depend on components and material preparation method. Composites BC/HAP are investigated and approved in many countries. It was shown that biomaterials are biocompatible and can promote the proliferation and differentiation in vitro of stromal cells. Many works are devoted to improvement the properties of BC/HAP composite as a bone scaffold. But before in vitro and in vivo testing it is necessary to define the structure and features of components interaction of prepared composites. In this work the combination of high-resolution transmission electron microscopy, scanning electron microscopy and X-ray analysis allowed us to define structure and morphology of composites BC/HAP prepared by different methods: combined aggregation of BC and HAP suspensions, synthesis HAP in the BC environment (biomimetic approach), synthesis ВС in the presence of HAP nanoparticles. It was found that composites have different texture. In the sample prepared by method of combined aggregation regular adsorption phenomenon when c axis of HAP crystals are oriented parallel to (-110) plane of BC fibril was revealed. This orientation is similar to HAP/collagen in natural bone. In the other samples such regular adsorption phenomenon of nanoparticles on the microfibril surface is absence. However, using different ratio of components during synthesis of HAP nanocrystals in the BC environment it was found some morphology changes of nanoparticles. Using different methods of composite preparation and changing components ratio it can be produced a broad spectrum of biomaterials for medical practice. This work was supported by RFBR grant № 14-02-31258 mol_a.
O-51 OPTICAL TOMOGRAPHY REVEALS NANOMETER SCALE DYNAMICS AT TRANSITION ZONES OF ADHESIVE JOINTS
G. Jonusauskas
Bordeaux University [email protected]
In this report, I will present a use of Time Gated Optical Tomography [1] for the real-time acquisition of 2D in-depth images of polymers. This contactless, non-invasive and non-destructive high throughput imaging (up to 1000 images/second) make possible to study the processes ongoing in transition zones of interdiffusing polymers and in adhesive joints with a few µm depth resolution for determining polymer structure and a few nanometer resolution of diffusion zone width. Next to the short demonstration of principle of operation and performance of imaging system, I will present an analysis of processes ongoing in transition zones of interdiffusing compatible (PVA-EVAC) and incompatible (PMMA-SAN) polymer systems. A typical example of PVA-EVAC contact reflectivity evolution in time is presented in the Figure 1. A biexponential fit of reflectivity changes in square root delay time coordinate make possible easy extraction of diffusivity and solubility data whereas the analysis of raw data gives the phase distribution of polymer blend at given temperature.
0 5 10 15 200
50
100
150
Dif
fusi
on
len
gth
(n
m)
Time delay t1/2 (s1/2) Figure 1. Left – an example of in-depth image of two polymers, middle – the dynamics of reflectivity of PVA-EVAC40 contact at 65°C, inset – the biexponential fit of reflectivity, right – the dynamics of interpenetration depth of PVA-EVAC40 at 65°C. I thank Sandra Bosio for the development of some opto-mechanical components as well as the Région Aquitaine and CNRS-RAS exchange programs N° 23977 & 25140 for the financial support. [1] E. Bordenave, E. Abraham, G. Jonusauskas, J. Oberlé, C. Rullière, Optics Express, 2002, 10, 35.
O-52 STRUCTURE, MORPHOLOGY AND OPTICAL PROPERTIES OF HYBRID POLYMER NANOSYSTEMS BASED ON ZINC SELENIDE
NANOPARTICLES FOR BIOMEDICAL APPLICATIONS
T.E. Sukhanova1, S.V. Valueva1, M.P. Sokolova1, G.N. Matveeva1, M.E. Vilegzhanina1, A.A. Kutin1, A.Ya. Volkov1, R.Yu. Smyslov1, P.G. Ul’yanov2, V.K. Adamchuk2
1 - Institute of Macromolecular Compounds RAS, Saint-Petersburg, Russia 2 - St. Peresburg State University, Saint-Petersburg, Russia
Recently, the study on multifunctional hybrid nanosystems (HNS) based on semiconductor nanoparticles (NPs) and quantum dots (QDs), stabilized by various polymers, has increased considerably due to their exciting novel properties and a wide variety of applications. This paper presents an overview of our works related to novel HNCs based on zinc selenide (ZnSe) nanoparticles, stabilized by biocompatible water-soluble polymers and a new generation photostabilizer (PS) - the Photoditazin under different conditions of preparation, focused on designing of water-soluble, stable in biological environment and non-toxic HNCs [1-4]. It briefly covers the basic synthetic approaches to their preparation and mechanisms of formation. Current applications of such systems include, for example, use as fluorescent cellular labels, deep-tissue and tumor imaging agents, NP-mediated drug delivery systems, and more recently - as sensitizers for photodynamic therapy (PDT) in cancer treatment. PDТ is a significantly more sparing method in clinical practice than surgery or radiation therapy, under which the healing effect attained owing to the ability of PS to be selectively accumulate into the cancer cells [5]. However, the compounds usually used as PS trend to aggregate in the tissue, unstable and toxic what restricts their applications [2,3]. For the creation of new materials for selective PDT, we have synthesized and investigated the morphology, crystalline and electronic structure and optical properties of novel HNS based on ZnSe NPs. For their characterization, the combination of AFM, HREM, ED, SEM, XRD, XPS, DSC, IR, PL, DLS and UV methods were used. The possibilities for formation of stable complexes between different polymers - PMAA, PMETAMS, BSA and PVP, with NPs are demonstrated [1-4]. It is shown, that the individual and self-assembled structures of various morphology can be formed depending on conditions of synthesis: spheres, ellipsoids, plates, rods, irregularly shaped structures and torus. The relations between the components are defined, under which the nanostructures with the sizes of 5-200 nm are formed. Several important related issues such as nanostructures size distribution, surface coatings, tendency to aggregation and toxicity of the prepared nanosystems are also considered. The work is partially performed within the framework of the Scientific and Educational Center Nanostructures and Self-Organization in Functional Macromolecular Systems and Their Diagnostics. The authors are grateful to the Russian Foundation for Basic Research for a financial support (project No. 10-03-01075).
1. Sukhanova T.E., Valueva S.V, Vylegzhanina M.E., et al. // J. Surf. Invest.: X-Ray, Synchrotron and Neutron Tech. 2014. V.8. No.3. PP.484-493.
2. Sukhanova T.E., Vylegzhanina M.E., Valueva S.V., et al. // J. Surf. Invest.: X-Ray, Synchrotron and Neutron Tech. 2013. V.7. No.4. PP.761-679.
3. Sukhanova T.E., Bershtein V.A., Valueva S.V., et al. // Russ. J. Phys. Chem. 2014. V.88. No.3. PP.544-550.
4. Sukhanova T.E., Bershtein V.A., Valueva S.V., et al. // in Proc. 14th IUPAC Int. Symp. MacroMolec. Complexes MMC-14. Helsinki. Finland. 2011. P.64.
5. Gelfond M.L. Practicheskaya onkologiya. 2007. V.8. No.4. PP.204-210.
O-53 CONFORMATIONAL AND PHASE TRANSITIONS IN DNA SOLUTIONS WITH CHARGED COMPOUNDS
N.A. Kasyanenko, L.A. Lysiakova, Q. Zhang, G.V. Alexeev, I.N. Unksov
St.-Petersburg State University, Faculty of Physics [email protected]
DNA molecule in a water solution is a rigid and highly charged polyion. Its functional properties are largely determined by electrostatic interactions. However, in contrast to double-stranded helix , single-stranded molecule is a flexible amphiphilic polymer whose affinity with the solvent is very different from the native DNA. The conformational transitions of DNA induced by its interaction with different compounds are accompanied with sufficient changes in conformational parameters (volume of molecular coil, rigidity, secondary structures) without phase separation. In contrast to it, DNA condensation induced by multivalent ions, gene vector formation on the base of interpolyelectrolyte complexes, DNA monomolecular precipitation after the binding of surfactants are the typical phase transitions which can be used for the creation of different systems for the medicine and new technologies. The alternative way is to create the disperse systems as a result of metal ion reduction after the formation of their complexes with DNA. DNA as a template stabilized discrete nanoparticles and nanoclusters. Such systems have unique optical properties and can be used for the creation of new materials, sensors, samples for manipulations on a surface for nanoelectronics. The measurements were carried out by the methods of viscosity, flow birefringence, circular dichroism, dynamic light scattering, atomic force microscopy, spectrophotometry. The analysis of DNA conformation in the presence of metal ions, oligo- and polycations has been done. Phase diagrams for DNA-surfactant, DNA-polymer, DNA-oligomer systems were constructed. The comparison of multivalent ions and polycation influence on DNA conformation has been fulfilled. Experiments were partially implemented using equipment of Resource Centers of Saint Petersburg State University. Work was supported by a RFBR grant 13-03-01192A and SPbU grant 11.38.644.2013
O-54 POLYETHYLENE-BASED NANOCOMPOSITES WITH CARBON REINFORCEMENTS: ATOMISTIC AND COARSE-GRAINED
APPROACHES
N.D. Orekhov, V.V. Stegaylov Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS)
In the last years, nanotube-polymer composites have become a subject of interest in the materials science due to their extraordinary mechanical properties in combination with low density and high resistance to corrosion. It is of great interest to establish the link between nanostructure and macroscopic mechanical properties of nanocomposite, i.e., between type and concentration of reinforcements and toughness of material. Molecular dynamics gives the opportunity to build such multi-level models with great predictive capabilities. On the molecular level, nanoreinforcement-matrix interaction models predominantly use two different approaches: atomistic simulations and coarse-grained (CG) simulations. In this work, we discuss and compare the results of atomistic and coarse-grained simulations of polyethylene matrix with multiwall carbon nanotube (MWCNT) nanoreinforcements under different loading conditions. Simulations are held within single model so that properties of intra - and intermolecular interactions are transferred from atomistic to CG level. Besides the mechanical properties of the material attention is given to the accuracy maintenance during coarse-graining and its benefits in the context of parallel efficiency on high-performance supercomputers.
O-55 POLYSILOXANES FOR DIELECTRIC ACTUATORS AND THEIR MOLECULAR DYNAMICS
V.E. Musteata1, C. Racles2, M. Cazacu2, M. Alexandru2, A. Bele2, D.M. Opris3
1 - Petru Poni Institute of Macromolecular Chemistry, Polymer Physics Department, Iasi, Romania 2 - Petru Poni Institute of Macromolecular Chemistry, Laboratory of Inorganic Polymers, Iasi, Romania
3 - Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Functional Polymers, Dubendorf, Switzerland
Silicones with substituted lateral chains containing polar cyano groups were sythesized in order to increase their dielectric permittivity for dielectric elastomer actuators. The dielectric properties of these copolymers were measured in liquid state. The maximum permitivity value attainable with this chemical modification was 15.3. In order to obtain films with good mechanical properties, mixtures of cyano-modified polysiloxanes with different ratios of high molecular weight polydimethylsiloxane (PDMS) were made and crosslinked. By this method, an increase of permittivity from 2.4, tipical for polydimethylsiloxanes, to above 9 (at 1 kHz) was obtained. This would translate into increased electrical energy density allowing lower operating voltage required to induce the elongation. At the same time, the conductivity and loss tangent values remained low, of the order of 10-12 S/cm and respectively, less than 1 (at 1Hz). The variation of complex dielectric permittivity with temperature revealed two distinct α relaxations corresponding to dynamic glass transitions of the mixture components around -100 ºC. Another polarization phenomena was evidenced at higher temperatures, most probably due to accumulations of charges at the interphases between the two polymers with different electrical properties. In addition to the effect of polar groups, this interfacial polarization may be partly responsable for the increased values of permittivity. Acknowledgement: This work was financially supported by the Swiss Enlargement Contribution in the framework of the Romanian-Swiss Research Programme, under Project number IZERZO_142215 / 1, RSRP NR: 10 / RO-CH/RSRP/01.01.2013.
O-56 CONTROLLED DEFECTS IN POLY(ETHYLENE GLYCOL) NETWORKS BY SOL-GEL REACTION OF MONO- AND DI-FUNCTIONAL
PRECURSORS
G.A. George, B. Radi Queensland University of Technology, Faculty of Science and Engineering, Brisbane, Australia
Major defects in end-crosslinked polymers include unreacted or dangling chain ends that lower the crosslink density, so reducing elastic recovery and increasing solvent swelling. These defects are hard to detect, quantify and control when free radical reactions are used to form the network. An alternative approach that we have researched is the sol-gel synthesis of a poly(ethylene glycol) (PEG-2000) network using controlled amounts of bis- and mono- triethoxy silyl propyl urethane PEG-2000 precursors. This classic sol-gel reaction forms silsesquioxane (SSQ, R-SiO1.5) structures that provide network junctions with the number of dangling chains controlled by the ratio of mono- to bis-functionalized precursors. Micelle formation during synthesis results from the amphiphilic nature of the precursors and the sol-gel reaction initially occurs at the micelle/water interface that is stabilized by the attached PEG chains. Structures that may occur are shown below.
Dangling
Dangling
The sol-gel reaction has been studied by dynamic light scattering (DLS) and the networks have been characterized by 29Si solid state NMR, sol fraction and swelling measurements. The silsesquioxane (SSQ) networks show high connectivity, which reduces solvent swelling, degree of crystallinity and the crystal transition temperature compared to other end-linked PEG networks and those formed by free radical reactions.
O-57 VERY TOUGH AND EXTENSIBLE GELS THROUGH SIMPLE FREE RADICAL POLYMERISATION WITH A MACROCROSSLINKER
S.C. Moratti, L.R. Hanton, S. Goswami, C.J. Mcadam
University of Otago, Department of Chemistry, Dunedin, New Zeraland [email protected]
Gels are usually very weak and poorly elastic. Several methods have been developed that produce gels with outstanding compressive and/or tensile strength. These include double network formation, use of nanocomposites , and heterogenous crosslinkers. While the latter method produces good properties, to date it has required the use of special monomers. We show in this work that extremely tough gels can be produced through simple free radical polymerisation of standard monomers such as acrylamide with a specially constructed macrocrosslinker. The resulting gel consisting of 80% water is extremely elastic, and can be stretched over 30 x without breaking -although at the highest extensions there is some permanent non-elastic deformation. It is also extremely resilient in compression, and can be compressed to over 97% of its original length. The toughness of these gels appears to originate from two factors. The relatively heterogenous network means that the crosslinks are fairly evenly distributed, which produces maximum extensibility. There is also just enough irreversible creep to help stop crack propagation. These gels are stable for months and can be constructed in a few hours at mild temperatures. These properties make it equal to the best nanocomposite gels, and much more extensible that the double network gels.
O-58 NEUTRON STUDIES OF COMPOSITES OF POLYPHENYLENE OXIDE MODIFIED BY HYBRID STAR-SHAPED FULLERENE-
CONTAINING MACROMOLECULES
V.T. Lebedev1, Yu.V. Kulvelis1, D.N. Orlova1, E.L. Krasnopeeva2, L.V. Vinogradova2 1 - B.P.Konstantinov Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, Saint-Petersburg,
Russia 2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia
Film composites of poly(2,6-dimethyl-1,4-phenylene oxide) modified by hybrid star-shaped polymer (1, 3 and 5 % wt.) with fullerene C60 branching centre and the arms of non polar polystyrene an polar diblock-copolymer of poly-2-vilylpyridine –block-poly-tert-buthyl methacrylate) have been studied by small-angle neutron scattering. The scattering analysis for dry, in deuterated methanol swollen and finally dried matrix polymer and composites has indicated the solvent filled the diffusion channels. This has given to them a high contrast in protonated matrix. It enabled us not only to study the methanol distribution in swollen membranes but also to determine the geometry of diffusion channels. First there were observed highly branched channels in matrix polymer. However, the evaporation of solvent from the matrix caused a dissipation of channels, and the matrix became more uniform. Oppositely to this, in the composites the increase of star-shaped polymer fraction caused the formation of stable linear channels. The AFM studies of morphology of composite films have shown their micro-domain structure in which the amount and size of domains are defined by star-shaped polymer fraction. Indeed, the domains contained nitrogen atoms (up to 1.8 % wt.). This confirmed a segregation of star-shaped molecules with polar arms having poly-2-vinylpyridine blocks, while the domain regions involved matrix chains also.
O-59 FORMATION PRINCIPLES OF A REGULAR STRUCTURE OF HIGH-STRENGTH LOW-TEMPERATURE CURING POLYURETHANES
E.R. Volkova, V.V. Tereshatov
Institute of Technical Chemistry of Ural Branch of the RAS [email protected]
An integrated approach to formation of low-temperature quickly curing high-strength constructional polyurethanes has been offered. This approach is based on the use of the mixed oligoetherpolyols combined with catalytically active N,N,N',N'-tetrakis-(-2-hydroxypropyl)-ethylendiamine and with an additional catalyst for urethane formation instead of individual polyols. Investigation in the reaction kinetics of urethane formation for selected components of the olygomer mixture has led to ascertainment of the fact that sequential addition of isocyanate, of oligoetherpolyol with primary OH–groups, and of triol with secondary OH–groups to the said diamine results in formation of a regular structure with molecular fragments of catalytically active four-functional oligomer diamine as initial branching nodes.
Figure. A fragment of the inferred spatial network of hard polyurethane, and elements of the
structure: – ethylene diamine segment; – diol segment (soft segment); – urethane
group (hard segment); – triol segment; - - - – hydrogen bond. Introduction of additional catalyst into reaction mixture contributes to the growth of the NCO bond’s conversion; this phenomenon can be explained by catalytic action of the reaction product itself, namely of the «catalyst–isocyanate» complex, which then reacts with hydroxyl groups of polyol. A possibility of a targeted variation in physic-chemical properties of low-temperature quickly curing constructional polyurethane materials while modifying their structure has been demonstrated. A number of composites with rheological properties of the reaction mass which enable producing high-strength defect-free materials capable of complete curing at room temperature in a short space of time have been built. Acknowledgements. The work was financially supported by the Russian Foundation for Basic Research (project 14–03–00051) and by Ural Branch of the Russian Academy of Sciences (project 12–T–3–1002).
4 OCN-R-NCOHO OH
HO OHR'
O O
O OR'
-C-NH-R-NCO
OCN-R-NH-C-
OCN-R-NH-C-
-C-NH-R-NCO
OO
O O
2 HO-R"-OH
O O
O OR'
-C-NH-R-NH-C-O-R"-OH
OCN-R-NH-C-
OCN-R-NH-C-
-C-NH-R-NH-C-O-R"-OH
OO
O O O
O
OHHO-R"'-OH
+
OCN-R-NCO
+ +
I
II
Diol
Triol
Polyisocyanate
III
O-60 STATISTICAL ANALYSIS OF POLYLACTIDE/POLYHYDROXYALKANOATE BLENDS MORPHOLOGY
S.V. Bronnikov1, A.V. Podshivalov2, T. Gerard3, T. Budtova3 1 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russia
2 - National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia 3 - Mines ParisTech, Centre de Mise en Forme des Materiaux, Sophia Antipolis, France
The blends of immiscible biodegradable polymers, polylactide and poly(hydroxybutyrate-co-hydroxyvalerate), varying in composition (from 0/100 to 100/0 wt %) were prepared by melt mixing. For investigation of their morphology, the SEM images of the blends were segmented, treated statistically, and the size distributions of the minor-phase droplets were described with principles of irreversible thermodynamics. Two statistical ensembles involving dispersed and coalesced minor-phase particles were found. When a content of the minor phase was low (≤ 10 wt %), only dispersed particles of the minor phase were found, whereas at the higher minor-phase concentration, both dispersed and coalesced minor-phase particles were observed. The mean diameters of both dispersed and coalesced minor-phase particles were calculated and plotted against blend composition. The mean diameter of the dispersed minor-phase particles was shown to be small (about 1 μm). It increases only a bit with increasing the minor-phase content, whereas the mean diameter of the coalesced particles was found to increase more considerably and achieves ca. 5 μm for the 50/50 wt % composition.
O-61 REINFORCEMENT OF FILLED ELASTOMERS: LINEAR AND NONLINEAR MECHANICS VS LOCAL DYNAMICS
C. Batistakis, M.A.J. Michels, A.V. Lyulin
Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, Eindhoven, The Netherlands [email protected]
We present results of the molecular-dynamics simulations carried out [1-3] for the bead-rod coarse-
grained polymer melt capped between two attractive crystalline substrates, see the Figure on the left. The main purpose of our research is to study the rigidity of the polymer films in the linear and non-linear regime of mechanical deformation, and to compare the findings with the layer-resolved polymer segmental dynamics. The simulated density profiles show a monomer layering at the polymer-substrate interface, with a higher density compared to the middle-film bulk. The temperature- and thickness dependence of the film-averaged density were measured for all polymer films. Decreasing the film thickness leads to an increase of this density and of the film-averaged glass-transition temperature. Layer-resolved segmental dynamics of the thickest films
shows a gradient of the mobility upon approach of the polymer-substrate interface, while the middle-layer dynamics exhibits bulk-like behaviour. With decreasing film thickness, these gradients overlap. All polymer films were deformed uniaxially normal to the substrates beyond their linear viscoelastic regime; their elastic and secant moduli were extracted.We found that the mechanical reinforcement in the simulated films is in line with their glass-transition temperatures. We proved that the drop in the film rigidity under deformation can be described by the changes in the layer-resolved relaxation times under the same deformation amplitudes. 1. C. Batistakis, A.V. Lyulin and M.A.J. Michels, Macromolecules, 2012, 45, 7782. 2. C. Batistakis, M.A.J. Michels, A.V. Lyulin, J. Chem. Phys., 2013,139, 024906. 3. C. Batistakis, A.V. Lyulin, Comp. Phys. Commun., 2014, in print.
O-62 FABRICATION OF WHEAT GLUTEN/CHITOSAN/GRAPHENE OXIDE BIODEGRADABLE NANOCOMPOSITE MEMBRANES
C.S. Ha1, D.B. Lee1, J.J. Park1, Y. Shchipunov2
1 - Dept. of Polymer Sci. and Eng., Pusan National Univ., Busan 609-735, Korea 2 - Institute of Chemistry, Fas East Department, Russian Academy of Sciences, Vladivostok, Russia
Petroleum-based synthetic polymers are used for various applications. As a result, severe disposal and environmental problems have been created because of the inability of natural organisms to degrade these polymers. Considerable efforts have been made to develop biodegradable materials from renewable resources such as agricultural byproducts. Natural polymers derived from agricultural products (such as starch, proteins and cellulose) are the major resource for developing renewable and biodegradable polymer materials. Proteins are the natural heteropolymers which are constituted by many different kinds of amino acids. Among them, wheat gluten has received attention because of its unique viscoelastic and thermoplastic properties. In this work, we present a simple and green approach to fabrication of wheat gluten (WG) /chitosan (CS) /graphene oxide (GO) nanocomposite films. WG/CS/GO nanocomposite films are prepared in a casting and solvent evaporation method. Fourier transform Infrared (FT-IR) spectroscopy, X-ray diffractions (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), tensile testing, and moisture uptake are used to study the structure and properties of these nanocomposites. With incorporation of 1 wt% of GO, the fracture strength and tensile modulus of the nanocomposites are significantly enhanced by 33% and 45%, respectively. Water absorption measurements showed that the water absorption ratio of the WG/CS/GO composites decreased from 200 to 125%, and the barrier properties were obviously improved. Results suggest that the incorporation of graphene oxide can improve the properties of the wheat gluten-based composites due to the synergistic interaction and hydrogen bonding between GO, CS, and WG. Acknowledgements The work was supported by the National Research Foundation of Korea(NRF) through the NRF- Russia Foundation for Basic Research (RFBR) Joint Research Program.
O-63 SELF-ORGANIZATION IN LOW CONCENTRATION AQUEOUS SOLUTIONS OF L-CYSTEINE AND ITS DERIVATIVES. THEORY AND
EXPERIMENT
P.M. Pakhomov1, S.D. Khizhnyak1, M.M. Ovchinnikov2, P.V. Komarov1 1 - Tver State University, Tver, Russia
2 - Tver State Medical Academy, Tver, Russia [email protected]
Sulfur-containing amino acids are interesting candidates for gelation as they can be self-assembled using various non-covalent interactions in water including H-bonding, electrostatic and hydrophobic interactions. A novel gel-forming supramolecular systems based on aqueous solutions of amino acid L-cysteine, silver nitrate in excess and same electrolytes are discovered by the authors. L-cysteine is a unique amino acid, it has three functional groups – thiol, carboxyl and amino. Peculiarities of the systems are gelation at the low concentrations of the initial components (~0,01%), high antimicrobical activity, compatibility with the substances of another nature, that gives an opportunity to create highly efficient pharmaceutical preparations. On the base of experimental and theoretical data mechanism of gelation is suggested. It is supposed that silver mercaptide, obtained on the first stage of reaction between L-cysteine and silver nitrate, can form linear supramolecular chains due to non-covalent bonds. That is so called ageing of cysteine-silver nitrate solutions and in the dependence on temperature (15-35 0C) its duration is varied from some minutes to hours. The self-organization process occurs only in definite concentration range of the initial components and is a required stage for gelation, which is induced by electrolytes (salts, acids or alkali). The linear supramolecular chains can be considered as molecular precursors for building up the gel-network. Role of “binders” for joining of the chains belongs to electrolyte anions. In dependence on a type of the electrolyte, structure and properties of the hydrogels are varied, that is confirmed by means of viscometry and TEM. Moreover, it is found out that N-acetyl-L-cysteine (NAC) and silver nitrate also form hydrogels at low concentrations. In a NAC molecule in contrast to L-cysteine a hydrogen atom of the amino group is substituted with an acetyl group that changes acidic-base properties of the molecule and charge distributions of the functional groups. As a result, gelation in the NAC system is a one stage process occurring in a narrow range of pH at molar ratio of the initial components 1:1. The NAC based gel is weaker in comparison to the gels based on L-cysteine and less stable over time. TEM data showed that three-dimensional network of the NAC gel consists of nanofibers with high aspect ratio. To clarify a role of each L-cysteine functional group in the gelation process, self-organization in aqueous systems of L-cysteine derivatives: cysteamine (CA) – AgNO3, 3-mercaptopropionic acid (MPA) – AgNO3 and their mixture (1:1) is studied by dynamic light scattering (DLS), UV-vis spectroscopy and transmission electron microscopy. We have found that there is aggregation in the systems and formation of supramolecular chains -Ag-S(R)-Ag-S(R)- occurs also in cases of absence of carboxyl groups (CA) and amino groups (MPA). Thus, to elucidate in details mechanism of the formation of the oligomeric chains, clusters, gel, it is necessary to vary the structure of thiol containing substances and a type of anion which reacts with the thiol group. The study of L-cysteine derivatives and L-cysteine based gel-forming systems will be continued.
O-64 PARTITIONING OF SALT BETWEEN POLYELECTROLYTE GELS AND BULK SOLUTION: GRANDCANONICAL SIMULATIONS VS.
NUMERICAL POISSON-BOLTZMANN MODEL AND ANALYTICAL DONNAN THEORY
T. Richter1, P. Kosovan2, C. Holm1
1 - Institute for Computational Physics, University of Stuttgart, Stuttgart, Germany 2 - Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Czech
Republic [email protected]
We employed grandcanonical hybrid molecular dynamics / Monte Carlo (MC/MD) simulations to study swelling equilibrium of polyelectrolyte gels in salt solution. We compare our simulation results at for various polymer parameters (degree of charging, chain length) and various salt concentrations in the bulk solution. The simulation results are in qualitative agreement with simple Donnan theory for the osmotic pressure of ions, combined with Gaussian model for the network elasticity. The comparison reveals systematic deviations especially at high charge fractions. They hint towards further improvements of the theoretical model by inclusion of inhomogeneous distribution of ions in the gel, with their preferential location near the polymer. In an augmented model, we treat the ion distribution within the Poisson-Boltzmann framework, which leads to an improved agreement between the theory and the simulation data.
Figure: Ratio of the salt concentration inside the gel, as a function of concentration of charged groups in the gel. The Donnan theory (solid line) predicts a universal behaviour independent of polymer paramters. The simulation data collapse on three different curves for the three different degrees of charging of the polymer (f) while chain length (N) seems to have little influence.
O-65 MINERALIZATION OF BIOPOLYMERS AS A ROUTE FOR FUNCTIONAL MATERIALS PREPARATION
Y.A. Shchipunov, I.V. Postnova, I.V. Semiletova, O.N. Khlebnikov Institute of Chemistry, Russian Academy of Sciences, Vladivostok, 690022 Russia
There are numerous examples of hierarchically structured and highly efficient functional materials from mineralized organics in the living nature. The development of biomimicking methods is an area of tremendous activity for engineering advanced materials with regulated structural organization and functionalities through easier processability without using an acid or alkali and organic solvents. Here some examples of biomimicking mineralization used for fabrication of biopolymer-silica bionanocomposites at mild conditions with sensoring, luminescent, photonic and biocatalytic properties are presented. The key aspect of our approach was in the silica precursor. Instead of generally applied tertraethoxysilane, which is incompatible with biopolymers, tetrakis(2-hydroxyethyl) orthosilicate (THEOS) with ethylene glycol residues was applied. The exchange of ethanol for the ethylene glycol separated after the hydrolysis made it biocompatible with biopolymers. Furthermore, some bionanocomposites possessed the transparency needed for optical applications. Sensoring materials were constructed on the basis of polysaccharides conjugated with acid-base dyes. The comjugation prevented the leakage of water-soluble low molecular substances from inorganic matrix, providing the pH sensitivity of spectral response. The luminescent properties were imparted by europium complexes. To entrap them into silica, amylose was taken. This polysaccharide being in helical form can form inclusion complexes with nonpolar substances. It was used to develop materials with high red luminescence. High third-order nonlinear susceptibility and high-speed optical response was found in hyaluronan-silica nanocomposites. It was responsible for the generation of a filamentous intense white light (supercontinuum) owing to the spectral broadening of initial ultra-short laser pulses of 40 fs duration propagating through samples. The phenomenon was modulated by gold nanoparticles stabilized by the polysaccharide. Biocatalysts were prepared by encasing enzymes into inorganic matrix via the same mineralization. The developed method is ideally suited for this purpose. Its main advantage over current techniques lies in that the entrapment conditions are dictated by an enzyme, but not the processing. We could immobilize very labile proteins that lose their activity after the separation even at the appropriate conditions within few hours. The entrapment into the inorganic matrix resulted in a sharp increase of their lifetime. They demonstrated sometimes even enhanced enzymatic activity in comparison with the initial solutions.
O-66 TRANSPORT PROPERTIES OF POLYMER MEMBRANES: CONTACT ANGLES DATA
Yu.G. Bogdanova, V.D. Dolzhikova
Moscow Lomonosov State University [email protected]
The surface free energy (γSV) of amorphous polymers films was determined using contact angle measurements (Owens-Wendt-Kaelble approach). Polymers (polynorbornenes, polythrimethylsilylpropine (PTMSP), polymethylpentine (PMP)) were synthesized and characterized in Topchiev Institute of Petrochemical Synthesis. Also commercial objects Teflons AF (Du Pont) and Hyflones AD (Solvay-Solexis) were used. It was found that the dispersive component (γd
SV) makes the major contribution in γSV value. The correlation of γd
SV with literature data about gas permeability of polymer membranes and fractional free volume (FFV) of polymers was found. The results obtained were explained with position of similarity of contact interactions between the solid spherical particles and centers of masses of polymer coils in polymer films. Wetting of PTMSP and PMP films with alcohol solutions was studied. Ethanol, propanol-1, propanol-2 and butanol-1 were used. Also the surface tension γLV of aqueous alcohol solution of different concentrations (c) was measured. The isotherms of wetting strain γLV·cosθr = f (c) were analyzed using receding contact angles θr to simulate the process of nanofiltration of liquid mixtures through the continual polymer membranes. The concentration corresponding to maximum of γLV·cosθ = f (c) depends on FFV of polymer and the alcohol hydrocarbon chain length. It was proposed that these concentrations correspond to the beginning of alcohol sorption in polymer film. So, new perspectives of contact angle measurements for prediction of polymer membrane efficiency with respect to gas and liquid transport were demonstrated. This work was supported by Russian Foundation of Basic research, projects № 14-08-00893а, № 10-03-00142а.
O-67 STRUCTURE-PROPERTY RELATIONSHIPS OF PP-BASED COMPOSITE FIBERS WITH VGCF NANOFILLER
E.M. Ivankova1, I.A. Kasatkin2, O.A. Moskalyuk3, A. Bugrov2, V.E. Yudin1, J.M. Kenny1
1 - Institute of Macromolecular Compounds RAS 2 - Petersburg State University, Universitetskaya nab. 7/9, St.Petersburg, 199034 Russia
3 - Saint Petersburg State University of Technology and Design, Bol’shaya Morskaya ul. 18, St.Petersburg, 191186 Russia
In the present work, the production of nanocomposite fibers consisting of isotactic polypropylene (iPP) as matrix and vapor grown carbon fibers (VGCF) as nanofiller followed by the fine structure and mechanical property characterisation has been studied. The obtained fibers have been investigated with the help of scanning electron microscopy (SEM) and X-Ray scattering (WAXS). The experimental results point out that the VGCFs aligned in the fiber extrusion direction are able to induce crystallization of the surrounding iPP matrix in a special way that follows the formation of oriented iPP -transcrystallite layers. The degree of crystalline structure orientation has evident VGCF content and draw ratio (DR) effect. When amount of VGCF and DR increases, the iPP α-crystalline reflections show rather strong azimuthal angle dependence that, in turn, indicates the formation of an anisotropic material structure. The improvements of the mechanical properties of the composite fibers both in undrawn and drawn states are attributed to the VGCF aligning during extrusion and induced highly oriented iPP crystalline structure rather then to the reinforcing effect of the nanofibers. A scheme explaining the way of the tensile strength changes from the structural point of view is proposed. Acknowledgements This study is supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002 (megagrant of the Government of the Russian Federation according to the Resolution No. 220 of April 9, 2010). The WAXS experiments were performed at the Research Center for X-Ray Diffraction Studies of St.Petersburg State University.
O-68 THE IMPACT OF ULTRA-LOW AMOUNTS OF REACTIVE SILICON-BASED NANOPARTICLES ON STRUCTURE AND PROPERTIES
OF THERMOSTABLE POLYCYANURATES
V.A. Bershtein1, A.M. Fainleib2, L.M. Egorova1, O.P. Grigoryeva2, D.A. Kirilenko1, S.G. Konnikov1, V.A. Ryzhov1, O.N. Starostenko2, P.N. Yakushev1, M.A. Yagovkina1,
K.G. Gusakova2 1 - Ioffe Physical-Technical Institute, RAS, 194021 St.-Petersburg, Russia
2 - Institute of Macromolecular Chemistry, NAS, 02160 Kyiv, Ukraine [email protected]
Last decade the manufacturers of polymer matrices of composites for aerospace industry and microelectronics have increasingly used the high temperature densely cross-linked polycyanurate (PCN) networks which are characterized by a unique combination of properties. In this work, a few series of PCN nanocomposites with matrices formed by polycyclotrimerization of cyanate esters derived from Bisphenols E, A, 6F-A or Primaset PT-30 oligomer (Lonza Corp.) and designated as DCBE, DCBA, 6F-DCBA and PT-30 matrices, respectively, were prepared. They were doped with reactive silicon-based nanoparticles (NPs), viz., with 3-D epoxy cyclohexyl-functionalized polyhedral oligomeric silsesquioxane (POSS) molecules of about 1 nm in diameter or amino-functionalized 2-D silicate nanolayers (montmorillonite, MMT) introduced in the amounts varying from 0.01 to 10 wt.%. The nanocomposites’ structure, dynamics and properties were characterized in detail by FTIR, SAXS, TEM, DSC, DMA, TGA, Far-IR spectroscopy, laser-interferometric creep rate spectroscopy (CRS), and energy-dispersive X-ray spectroscopy (EDXS). FTIR spectra confirmed chemical hybridization of both constituents in these nanocomposites. It was revealed that, unlike the influence on matrices from linear polymers, ultra-low additives of NPs (starting from 0.025 wt.%), covalently incorporated into densely cross-linked PCNs, exerted the substantial impact on their nanostructure, molecular dynamics and improving thermal/mechanical properties due to enhanced long-range action of the “constrained dynamics” effect. The maximum action of NPs was registered for DCBE matrix. The effects observed regularly decreased or even became negative if NPs content increased from 1 to 10 wt.%. As TEM/SAXS/EDXS analysis showed, this was directly associated with cardinal changes in the character of NPs spatial distribution in the matrix and, to lesser extent, with the matrix nanostructure. Thus, introducing 0.025% NPs already generated structural nanoheterogeneity suggesting a quasi-periodic type of spatial distribution of NPs in the amorphous matrix (SAXS), and indicating POSS molecular or 1-3 MMT nanolayers’ dispersion within the nanocomposite matrix (TEM). With increasing NPs content from 1 to 10%, arising linear nanostructural inclusions, their stacking in multilayered formations, and formation of NPs aggregates of ~50 nm in size (POSS), or stacking of MMT nanolayers with a gradual increase in stack thickness were observed. Moreover, the significantly increased spread of local Si contents in the nanocomposites was revealed by EDXS at 5-10% NPs pointing on enhancing inhomogeneity of NPs distribution. In accordance with the structural data, dynamics and properties of the nanocomposites changed. Thus, far-IR spectra indicated the substantial impact of ultra-low POSS or MMT additives on matrix dynamics including suppression of triazine cycle librations (~80 cm-1) and changing character of torsional skeletal vibrations (160-230 cm-1). For neat matrices, Tg increased in a row of DCBE–DCBA–6F-DCBA–PT-30, e.g., was equal to 248, 275, 300 and 4000C, respectively (DMA, 1 Hz). Ultra-low NP additives resulted in a substantial increasing Tg and especially Tg onset (by 40-500), and enhanced dynamic heterogeneity. Moreover, increasing moduli by 1.5-3.0 times over the temperature range of 20-2000C and enhancing high temperature creep resistance, as well as a substantially improved thermal stability at the earlier stages of their degradation (at T < 4000C) were attained for the nanocomposites with ultra-low NP contents. The work was supported by RFBR Russian – DFFD Ukrainian project №13-03-90444 (F53.3/033) and carried out in part in Joint Research Center "Material Science and Characterization in Advanced Technologies" under the financial support from the Ministry of Education and Science of the Russian Federation.
O-69 POLYMER/PHOTOSENSITIZER FIBROUS MATERIALS WITH LIGHT-TRIGGERED ANTIBACTERIAL ACTIVITY
A.N. Severyukhina1, N.V. Petrova1, I.A. Mamonova2, I.V. Vidyasheva1, A.M. Zakharevich1,
A.A. Skaptsov1, N.A. Yurasov1, G.S. Terentyuk3, D.M. Puchinyan2, B.N. Klebtsov4, K. Smuda5, R. Georgieva5, H. Baumler5, D.A. Gorin1
1 - Saratov State University, Saratov, Russia 2 - Institute of Traumatology and Orthopedics, Saratov, Russia
3 - Saratov State Medical University named after V.I. Razumovsky, Saratov, Russia 4 - Institute of Biochemistry and Physiology of Plants and Microorganisms of RAS, Saratov, Russia
5 - Institute of Transfusion Medicine Charite Universitaetsmedizin, Berlin, Germany [email protected]
An emerging technology allows producing materials sensitive to external stimuli, such as light or laser irradiation, alternating magnetic field, ultrasound and etc. Stimuli responsive materials are playing an increasingly important role in a diverse range of areas, including drug delivery, diagnostics, tissue engineering, biosensors, coatings and textiles. Polymer nanofibers are a recently developed class of nanomaterials, which can be a perfect matrix for creation of stimuli responsive materials. Sensitivity to one or another external influence can be achieved by adding metal nanoparticles, photosensitizers and other supplements. This approach is one of the promising concepts for producing of multifunctional materials. For polymer nanofibrous synthesis, the electrospinning has been widely used as the most effective methods because of technological simplicity, versatility, low cost and possibility of producing continuous polymer fibers with diameters ranging from submicrons to nanometers [1, 2]. Electrospun nanofibrous materials have several outstanding characteristics, such as high surface area to volume ratio, high porosity, flexibility in surface functionalities and superior mechanical performance (e.g. stiffness and tensile strength). Therefore, various polymers have been successfully electrospun into ultrafine fibers for different applications in recent years. Thus, polymeric nanofibrous matrix is among of the most promising materials for medicine. A new approach in current nanotechnology is a combination of various methods for tissue-engineering and antimicrobial therapy. Studies by Michael R. Hamblin, Tayyaba Hasan [3] demonstrated the ability to apply PDT as a new approach of antimicrobial treatment. From this point of view the composite of polymer nanofibers/photosensitizer (Photosens) were fabricated. Photosens have been incorporated within the nanofibers by it addition to the polymer solution. Samples with different PS mass ratio (0%, 1%, 2.5%, 5% w/w) were prepared. The morphological features of these matrixes were analyzed by scanning electron microscopy. The biocompatibility properties of the material were verified through cell experiments with cancerous (human mammary adenocarcinoma MDA-MB-231 and human colorectal adenocarcinoma SW480) and non-cancerous (murine osteoblasts MC3T3-E1) cell lines. The data were examined with the help of confocal laser scanning microscope. The obtained images confirmed the activity of cell proliferation process. Cells were firmly attached and stretched over the fiber surfaces. An antimicrobial activity was observed by disk diffusion method against S.aureus and E coli under laser irradiation. Results showed that light-exposed samples produce enough singlet oxygen to kill the bacteria on their surface and the penetration of Photosens into the depth of agar enhances the effectiveness of that therapy. Results of this work can be used for creation of novel scaffolds for tissue engineering and materials with light-induced cytotoxic effect, including cancer cells. This study was partially supported by RFBR Research project No. 12-03-33088 and by the Marie Curie project (PIRSES-GA-2013-612673).
1. H. Fong, D. H. Reneker, in Structure formation in polymeric fibers, ed. D. R. Salem, Hanser, Munich, 1st edn., 2001, pp. 225–246.
2. J. M. Deitzel, J. Kleinmeyer, J. K. Hirvonen, N. C. Beck, Polymer, 2001, 42, 8163-8170. 3. M. R. Hamblin, T. Hasan, Photochem. Photobiol. Sci., 2004, 3, 436-450.
O-70 MECHANICAL AND THERMAL PROPERTIES OF ROOM TEMPERATURE SELF-CURABLE WATERBORNE POLYURETHANES
H. Sardon, L. Irusta, M.J. Fernandez-Berridi
Departamento de Ciencia Y Tecnologia De Polimeros e Instituto de Materiales Polimericos (POLYMAT), San Sebastian, Spain
Water-based polyurethanes (WPU) are replacing organic based systems as a consequence of their lower toxicity compared to solvent-based products. However, due to the presence of carboxylic groups, needed to disperse the polyurethanes in aqueous media, their thermal, mechanical and solvent resistant properties are reduced limiting their use. One interesting option in order to overcome the drawbacks of WPU, is to create an organic-inorganic interpenetrated network by means of the sol-gel process.1, 2 In this work two series of hybrid waterborne polyurethane dispersions based on isophorone diisocyanate, polypropylene glycol (IPDI/PPG), and polybutylene adipate (IPDI/PBAD), containing different amounts of alkoxy silane terminal groups, were obtained by means of the acetone process. These alkoxy silane groups are able to cure at room temperature forming an interpenetrated network (Figure 1).
Figure 1. Schematic representation of the curing process of WPU functionalized with alkoxysilane end-groups. 1. H. Sardon, L. Irusta, M. J. Fernández-Berridi, M. Lansalot and E. Bourgeat-Lami, Polymer, 2010, 51, 5051-5057. 2. H. Sardon, L. Irusta, A. González and M. J. Fernández-Berridi, Prog. Org. Coat., 2013, 76, 1230-1235.
O-71 ASSEMBLING OF METAL NANOSTRUCTURES WITH TUNED SIZE AND SPATIAL ORDER IN IRRADIATED POLYELECTROLYTES
A.A. Zezin1, V.I. Feldman2, S.S. Abramchuk2, E.A. Zezina2
1 - Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Sciences, Profsoyuznaya ul. 70, Moscow, 117393 Russia
2 - Department of Chemistry, Moscow State University, Moscow, 119991 Russia [email protected]
Metal-containing compounds provide special optical, electrical and magnetic properties as well as catalytic and antibacterial activity for polymer materials. The behaviour of metal polymer hybrids arises from sizes of nanoparticles (NPs) and theirs spatial order. Key problem of design nanocomposites materials is tuning of sizes, spatial distribution and morphology of NPs. The assembling of metal NPs via reduction of metal ions inside polymer systems is powerful and versatile tool for preparation of metal nanostructures. An ability of functional groups of polyelectrolytes to bind metal ions offers wide possibilities for their application as precursors for preparation of polymer-metal hybrids. The main advantages of ionization radiation for the preparation of NPs involve a control over the formation of reducing radiolysis products and controlled changes in the rate of reduction of metal ions in a broad interval. The electron accelerators and γ- and X-ray radiation sources were used for nanoparticles obtaining. The structure of the nanocomposite materials at different stages of formation was examined using diffraction analysis, electron microscopy and optical spectroscopy. This contribution considers the assembling of metal nanostructures both in macromolecular templates and polymer matrixes. The solutions, suspensions of polyelectrolytes or films of interpolymer or interpolyelectrolyte complexes were used as media for obtain both for nanoparticles of transient and noble metals. The structure of metal–polymer hybrid materials based on polymer films is dependent on the irradiation conditions, the type of reduced metal ions, and their initial content in polymer matrices. The formation of nanoparticles in irradiated IPEC films is controlled by the transport of radiolysis products and the migration of metal ions through the polymer matrix. Variations in radiation parameters provide various types of reduction on the surface of a film and inside the film and make it possible to prepare both composites with NPs that are uniformly distributed in the polymer matrix and materials with a regular spatial distribution of NPs across the film thickness, including localization of nanostructures in the subsurface layers. It was found that in irradiated solutions the star-shape polyacrilic acid macromolecules comprising copper ions act as individual nanosized microcontainers for assembling of metal NPs by radiation induced reduction of cooper ions. The assembling of metal nanoparticles in the polyacrylic acid based polyelectrolate systems (not only amphiphylic copolymers but multicomponent suspensions) leads to obtaining of hybrids with specific spatial organization of NPs. The reason for such behavior may be explained by the effect of specific interaction of polyacrilic acid anions with positively charged surface of copper nanoparticles. The ratio between the rate of nucleation and the rate of growth of nanoparticles in the matrices of polyelectrolyte systems depends on the dose rate and on the mechanisms of reduction of metal ions and formation of clusters. The role of polyelectrolyte interaction with metal ions/surface to manipulate the nucleation and growth of nanoparticles in solution-phase syntheses are discussed. This study was supported by RFBR Research project No. 12-03-00762.
O-72 HYPERCROSSLINKED POLYSTYRENE NETWORKS: AN ATOMISTIC MOLECULAR DYNAMICS SIMULATION COMBINED WITH
A MAPPING/REVERSE MAPPING PROCEDURE
V.V. Vasilevskaya, A.A. Lazutin, M.K. Glagolev A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow, Russia
Hypercrosslinked polystyrene networks were first reported in the early 1970s [1]. Now the hypercrosslinked polymer gels are used in routine practice in many industrial applications [2-3] and are prepared from variety of polymers of different chemical structure and composition [3]. Mainly, the hypercrosslinked gels are formed by a fast and multiple crosslinking of macromolecules swollen in a good solvent. The swollen conformational state is entrapped (quenched) by a large number of crosslinks forming inter- and intramolecular bridges simultaneously in a whole volume. The resultant gels have a specific inner porous structure and bear significant inner stress in a dry state. To study the details of structure of hypercrosslinked gels we have simulated the process of crosslinking of linear polystyrene macromolecules swollen in dichloroethane by monochlorodimethyl ether. We started with atomistic modeling of solution of polystyrene in dichloroethane, then the results of simulation were used to create coarse-grained mesoscopic model which was employed for the simulation of crosslink reaction. The results of the coarse-grained simulations were reverse-mapped into full atomistic structure and after intensive simulations were analysed. It is found that in the course of crosslinking synthesis the crosslinks are distributed not uniformly. In such gels some fraction of phenyl rings has two methylene bridges while other phenyl rings have no crosslinks at all [4]. The inhomogeneous distribution of crosslinks leads to the effective microphase separation of polymer resulting in the formation of densely packed polymer fields and empty voids (see figure).
Seemingly due to such structure the hypercrosslinked gel has rather high elastic module and large specific surface. The calculated values of elastic modules and specific surface are in reasonable quantitative correspondence with experimental data. However, the density of dry gel determined as the ratio of total atomic mass to cell volume in vacuum is higher than experimentally determined values of apparent density. We believe that it could be explained, on the one hand, by the specificity of experimental determination of density of porous material and, on the other hand, by the limitations introduced in the model of synthesis simulations.
1. S.V. Rogozhin, V.A. Davankov, M.P. Tsyurupa, Patent USSR 299165 (1969). 2. M.P. Tsyurupa, V.A. Davankov. Reactive & Functional Polymers, 66, 768 (2006). 3. J. Germain, J. M.J. Frechet, F. Svec. SMALL, 5, 1098 (2009). 4. A.A. Lazutin, M.K. Glagolev, V.V. Vasilevskaya, A.R. Khokhlov. J. Chem. Phys., n.13,
140 (2014) The financial support is provided by the Russian Foundation for Basic Research (project № 14-003-00073).
O-73 THERMOPLASTIC POLYIMIDES: STRUCTURE-PROPERTIES RELATIONSHIP
S.V. Lyulin1, S.V. Larin1, V.M. Nazarychev1, S.G. Falkovich1, A.A. Gurtovenko1, A.V. Lyulin2
1 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russia 2 - Technische Universiteit Eindhoven, Theory of Polymers and Soft Matter Group, Eindhoven, The Netherlands
Revealing the way of how modification of the chemical structure of a polymer affects its macroscopic physical properties offers an opportunity to develop novel polymer materials with pre-defined characteristics. To address this problem we employ microsecond atomic-scale molecular dynamics simulations to get insight into the structural, thermal, and mechanical properties of heat-resistant bulk polyimides (PIs). We found a dramatic impact of electrostatic interactions for correct simulation of all considered PIs (R-BAPS, R-BAPB and R-BAPO which were synthesized in IMC and commercial PIs ULTEMTM and EXTEMTM). We demonstrate that macroscopic characteristics of polyimide samples (such as the glass transition temperature Tg, Young’s modulus, and density) are not particularly sensitive to the degree of equilibration. However, great caution should be paid when local structural characteristics are considered: proper equilibration of the local polymer structure is found to require simulations on a microsecond time scale, especially for polyimide-based nanocomposites. In contrast to the glass-transition temperature, the volumetric coefficient of thermal expansion (CTE) does not depend on the cooling rate in the low-temperature domain (T<Tg) so that comparison of computational and experimental values of CTE provides a much safer way for proper validation of the theoretical model. All computer simulations have been carried out using the computational facilities of the Institute of Macromolecular Compounds, Russian Academy of Sciences, and supercomputers “Chebyshev” and “Lomonosov” of the Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002
O-74 CARBON NANOTUBE INDUCED PRE-CRYSTALLIZATION OF POLYIMIDE: MOLECULAR DYNAMICS SIMULATION
S.V. Larin1, V.M. Nazarychev1, S.G. Falkovich1, A.A. Gurtovenko1, A.V. Lyulin2, S.V. Lyulin1
1 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russia 2 - Technische Universiteit Eindhoven, Theory of Polymers and Soft Matter Group,Eindhoven, The Netherlands
Innovative polymer nanocomposite materials (PNM) attract great attention during last several decades due to high potential to develop PNMs with unique characteristics including thermophysical, mechanical and electrical ones. The properties of PNM are defined mainly by interactions of polymer and nanofiller in the interface region and changes of polymer matrix microstructure there. Thus, even small addition of nanofiller to polymer matrix could lead to sufficient changes of material properties in comparison with unfilled polymer matrix due to high specific surface area of nanoparticles. Understanding of the influence of polymer chemical structure and PNM composition on the structure of polymer binder and properties of a composite plays the key role in the development of new PNM. Computer simulation is one of the most advanced methods that can be used to solve this problem. In the present study we investigate structural properties of nanocomposites based on thermostable thermoplastic polyimides (PIs) based on 1,3-bis-(3’,4-dicarboxyphenoxy)-benzene (dianhydride R) and various types of diamines: 4,4’-bis-(4”-aminophenoxy)-diphenyl (diamine BAPB) and 4,4’-bis-(4”-aminophenoxy)-diphenylsulfone (diamine BAPS). Both PIs were synthesized and intensively studied in the IMC RAS. These polymers have rather similar chemical structure. The only difference is the presence of sulphone hinge group in the diamine fragment of R-BAPS monomer unit. Computer simulations of nanocomposites filled with carbon nanotube (CNT) were performed on a microsecond timescale that is enough to equilibrate considered nanocomposites using most detailed atomistic molecular dynamics (MD). The specifics of polymer matrix structure in the vicinity of CNT surface were analyzed in details. The thickness of the interface region in the nanocomposites considered was estimated using pair correlation functions and distributions of polymer density relative to CNT axis. It was found to be close to 0.5 nm. The pair distribution functions in the PNM which are generally used to describe its structure, do not clarify the interrelation between the composite microscopic structure and the polymer chemical composition. Thus, some additional characterization of the subsurface layer microstructure is needed. In order to describe the subsurface layers of the polymer matrix in PNMs, we have calculated the distribution of the angle between the CNT axis and vectors defining the position of flat fragments of PI monomer units and order parameter for these vectors. In the R-BAPB based composites the formation of layered structure were observed where flat fragments of polymer chains are oriented along the CNT axis both close to and apart the nanofiller surface. Such ordering may be considered as initial stage of polymer matrix crystallization that occurs in PNMs. At the same time in R-BAPS based composites orientational ordering of flat fragments was observed only close to the CNT surface region. Also the change of the size and shape of polymer chains occurs for nanocomposites studied in comparison to these in unloaded PI samples. In the R-BAPB based composite PI chains are sufficiently elongated in the direction of the CNT axis whereas in the R-BAPS based composites polyimide chains are more compact than in bulk. Thus, we can conclude that the CNT can induce the pre-crystallization of the R-BAPB polyimide that was shown using atomistic MD simulations for the first time. The results observed are in agreement with available experimental data. The simulations have been performed using the computational facilities of the Institute of Macromolecular Compounds, Russian Academy of Sciences, and the Chebyshev and Lomonosov supercomputers at Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002
O-75 MULTISCALE SIMULATIONS OF POLYMER ELECTROLYTE MEMBRANES
P.V. Komarov1, P.G. Khalatur2, A.R. Khokhlov3
1 - Institute of Organoelement Compounds, R A S, Moscow, Russia 119991 2 - Institute for Advanced Energy Related Nanomaterials, Ulm University, Ulm D-89069, Germany
3 - M.V. Lomonosov Moscow State University, Moscow 119899, Russia [email protected]
We report results of multiscale simulations of hydrated ionomer membranes based on sulfonated poly(ether ether ketone)s (sPEEK) and Nafion that constitutes an important class of promising membrane materials for fuel cell applications. Using first-principles molecular dynamics simulations (ab initio MD), classical atomistic molecular dynamics simulations (AMD) and dynamic density functional theory (DDFT) we study the properties of proton transfer reactions and self-organization in the membranes. At the same water content, AMD and DDFT simulations predict very similar structures of the hydrated membranes. The observed morphology of water channels can be represented as a topologically complex sponge-like network consisting of irregular water-filled channels. Compared to Nafion, the channels in the sPEEK membrane are narrower and convoluted. Ab initio MD simulations have been performed to investigate the properties of protons transfer between sulfonic acid groups and water molecules. A comparison between sPEEK and Nafion serves as a guide in understanding the influence of water nanoconfinement on dissociation of the sulfonic groups in polymer electrolyte membranes with different chemical structures. The conducted simulations of charge migration in the water nanochannels allowed us to observe the bimodality of the van Hove autocorrelation function, which provides the direct evidence of the Grotthuss hopping mechanism as a significant contributor to the proton conductivity. The reported study was supported by the Supercomputing Center of M.V. Lomonosov Moscow State University.
O-76 MODELING OF ADDITION POLYMERIZATION IN HETEROGENEOUS MELTS
Y.V. Kudryavtsev1, E.N. Govorun2, A.V. Berezkin3
1 - Institute of Petrochemical Synthesis of RAS, Leninsky pr. 29, Moscow, 119991, Russia 2 - Faculty of Physics, Moscow State University, Leninskie Gory, Moscow, 119991, Russia
3 - Max-Planck Institut fuer Eisenforschung GmbH, Max-Planck str. 1, 40237 Duesseldorf and Technische Universitaet Muenchen, James-Franck-Str. 1, 85747 Garching, Germany
Heterogeneous polymerization of condensation monomers, which is widely used for in situ fabrication of micro- and nanocapsules and membranes, is nowadays adapted to 3D printing. Here we report on the first molecular simulation of this synthetic technique using dissipative particle dynamics and focusing on the reaction kinetics and characteristics of the polymer product. Depending on the miscibility of monomers and the ratio of characteristic reaction and diffusion times, the process goes through several kinetic regimes passing from reaction to diffusion control. Practically useful estimations of the boundaries between those regimes are proposed. The reaction-controlled regime is similar to homogeneous polymerization, whereas the typical features of interfacial polymerization are revealed under the diffusion control. Among them are high polydispersity growing with time and weak influence of the initial monomer molar ratio and the reaction rate on the polymerization degree. In agreement with the previous studies, we find that the polymer concentration and average chain lengths are spatially non-uniform. We also study polyaddition of miscible monomers by numerical solution of the reaction-diffusion equations derived for a few collective variables, the results being qualitatively consistent with the simulations. For immiscible monomers, the simulation results are confirmed by simple theoretical estimations. It is shown that ordering in the polymer film through microphase separation drastically decreases its permeability. This effect, which is not captured by the existing theories, is especially pronounced in the case of linear polymerization, whereas crosslinking suppresses self-organization and enhances mass transfer. Our results shed new light on the details of interfacial polymerization processes and demonstrate high potential of molecular simulations in this field. The work was supported by the Russian Foundation for Basic Research (project 12-03-00817a). We are also grateful for the opportunity to use computational cluster Chebyshev at the Moscow State University.
O-77 MOLECULAR INTERFACIAL EFFECTS IN BIOMIMETIC MINERALIZATION OF NATIVE AND CHEMICALLY MODIFIED
BACTERIAL CELLULOSE NANOFIBRILS
N.V. Lukasheva, D.A. Tolmachev Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Hybrid organic-mineral composites are the most promising materials for implants intended to replace bones. In order that the properties of these materials were similar to those of bones they are often produced by mimicking the natural process of mineralization (biomimetic route), namely, by soaking an organic matrix in calcium and phosphate ions containing solutions. Composites based on bacterial cellulose (BC) and calcium phosphates (CP) and synthesized via biomimetic route represent a new class of biomaterials designed for bone grafts. Generic mechanism for a biomimetic mineralization, as it is supposed, should be a heterogeneous crystallization, that is, mineral ions from the solution precipitate on molecules of the organic matrix, thereby forming CP crystallites. The concept of mineral formation from a solution on biologically active organic matrices typically involves two aspects: (I) the presence of surface functional groups of the matrix, which can cause the heterogeneous nucleation, and (II) increased saturation of the surrounding solution, which accelerates the process of nucleation and growth of mineral phase. BC is used in a native form or in a chemically modified form (when primary hydroxyl groups are replaced by ionizable groups). The mineralization mechanisms are regulated by molecular interfacial effects. To investigate the mechanisms of the biomimetic mineralization of native and chemically modified BC nanofibrils, quantum mechanics and molecular dynamics simulations have been performed. The influence of the partial atomic charge calculation protocol on the conformations of the cellulose molecules and on the nanofibrils structure as well as on the interfacial effects was studied. The influence of the solvation models applied in simulations was investigated also. It was established that the mechanisms of the nucleation of CP crystals regulated by native and chemically modified cellulose fibrils are different. Hydroxyl groups of native cellulose do not have a high enough reactivity to grow CP crystals. Though the oxygen atom of these groups bears a significant partial negative charge, the interactions between hydroxyl groups and Ca2+ ions (ion-polar interactions) in water solutions are very weak. The result is independent on the solvation model. Nucleation of CP crystals regulated by native BC is carried out in solution, that is, homogeneously. As it turned out, all types of the chemical modifications of BC (which are used in practice) do not lead to significant changes of the molecular conformations and the fibril structure. On the other hand, the interfacial interactions (the interactions of the charged fibril surface with ions and water molecules) are influenced by the magnitudes and the distributions of the partial atomic charges in the ionized groups. These characteristics are determined by the chemical structure of such groups, but it is necessary to choose the correct approach for their calculation. It was shown, that despite the differences in the estimates of these quantities obtained by the different approaches all the simulations demonstrated that the nucleation of CP crystals regulated by the chemically modified BC fibrils is carried out heterogeneously - on the fibril surface. The reported study was supported by RFBR, research project No. 14-03-32041.
O-78 CRITICAL CONFORMATIONS OF THE CHAINS IN A POLYMER MELT NEAR A SOLID SURFACE
A.M. Skvortsov
Chemical Pharmaceutical Academy, Prof. Popova 14, 197022 St. Petersburg, Russia [email protected]
Conformations of a polymer chain near a solid substrate at different concentrations are not only interesting from a fundamental point of view, but are also important for various applications, e.g., in coatings, lubricants, and composite materials, where these macromolecules control the overall performance of such systems. The conformations of a probe chain end-grafted at a solid surface in a sea of floating free chains of different concentration are analyzed by the self-consistent field method. Apart from the grafting, probe chain and floating chains are identical and represented by model with freely jointed chains on a six-choice lattice (a few data were generated for a five-choice lattice chains). These coarse-grained models describe the equilibrium properties of flexible atactic polymer chains at the scale of the segment length. The concentration was varied over the whole range from 0 (single grafted chain) to 1 (probe chain in the melt). The number of contacts with the surface, average height of the free end and its variance, average loop and train length, tail size distribution, end-point and overall segment distributions were calculated for a grafted probe chain as a function of for several chain lengths and substrate/polymer interactions, which were varied from strong repulsion to strong adsorption. The computations [1] show that the conformations of the probe chain in the melt do not depend on substrate/polymer interactions and are very similar to the conformations of a single end-grafted chain under critical conditions, and can thus be described analytically. These results are compared with Molecular Dynamics simulations [2] of the coarse-grained, bead-spring model of the polymer chains in melt near solid surfaces with repulsive and attractive interactions. The agreement of both results for lattice and off-lattice model chains are demonstrated. Acknowledgement. This work is supported by the Russian Foundation for Basic Research (grant 13-03-91331-NNIO_a). [1] A. M. Skvortsov, F. A. M. Leermakers, and G.J. Fleer, J. Chem. Phys. 2013, 139, 054907. [2] J. Sarabadani, A. Milchev, and T.A. Vilgis, J. Chem. Phys. 2014, in press.
O-79 PARTIAL CHEMICAL DOPING OF SEMICONDUCTING POLYMERS FOR ORGANIC ELECTRONIC DEVICES
Y. Kim, S. Nam, J. Jeong, J. Seo, S. Lee, H. Lee, H. Han, E. Kwak, H. Kim
Kyungpook National University [email protected]
Great attention has been paid to organic semiconducting materials due to their advantages featuring the fine control of device performances by molecular structure designs and the low-cost fabrication of devices by low temperature solution processes. Organic light-emitting devices (OLED) are the first examples that are commercialized using organic semiconducting materials [1], while organic solar cells (OSC), organic field-effect transistors (OFET), organic memory devices (OMEM) etc are heavily studied and considered to be commercialized soon [2-4]. Although the performance of organic electronic devices is being gradually improved, the major limiting factor leading to the low performance of organic electronic devices is attributed to the poor charge transport characteristics of organic semiconducting materials. One of the core reasons can be assigned to the imperfect ordering of organic molecules, which is more serious for semiconducting polymers than semiconducting small molecules owing to the long chains leading to a complex molecular stacking/alignment state. To improve the charge carrier mobility of semiconducting polymers, most of studies have been concentrated on improving the crystallinity of semiconducting polymers. However, the enhancement of polymer crystallinity is quite limited by the original chemical structure of polymers. Hence we have recently tried a simple but powerful approach by employing partial chemical doping techniques [5-8]. This presentation will show the chemical doping approaches of semiconducting polymers and their applications for organic electronic devices such as OFETs, OSCs and OMEMs. References [1] Y. Kim and C-S. Ha, Advances in Organic Light-Emitting Device, Trans Tech Publications, Switzerland (2008). [2] Y. Kim, K. H. Bae, Y. Y. Jung, D. K. Choi, and C-S. Ha, Chem. Mater. 16, 5051 (2004). [3] Y. Kim, S. Cook, S. M. Tuladhar, S. A. Choulis, J. Nelson, J. R. Durrant, D. D. C. Bradley, M. Giles, I. McCulloch, C-S. Ha, and M. Ree, Nature Mater. 5, 197 (2006). [4] M. Campoy-Quiles, T. Ferenczi, T. Agostinelli, P. G. Etchegoin, Y. Kim, T. D. Anthopoulos, P. N. Stavrinou, D. D. C. Bradley, and J. Nelson, Nature Mater. 7, 158 (2008). [5] S. Nam, M. Shin, H. Kim, C.-S. Ha, M. Ree, and Y. Kim, Adv. Funct. Mater. 21, 4527 (2011). [6] S. Nam, J. Kim, H. Lee, H. Kim, C.-S. Ha, and Y. Kim, ACS Appl. Mater. Interfaces 4, 1281 (2012). [7] S. Nam, M. Shin, S. Park, S. Lee, H. Kim, and Y. Kim, Phys. Chem. Chem. Phys. 14, 15046 (2012). [8] S. Nam, Y.-G. Ko, S. G. Hahm, S. Park, J. Seo, H. Lee, H. Kim, M. Ree, and Y. Kim, NPG Asia Mater. 5, e33 (2012).
O-80 EFFECT OF CURVATURE OF CARBON NANOTUBES ON THE EFFECTIVE PROPERTIES OF POLYMER COMPOSITES
R.V. Khudobin1, A.S. Kiselev2, E.S. Krutko2, S.A. Timan1
1 - N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences, Moscow, Russia 2 - NRC “Kurchatov institute”, Moscow, Russia
The effectiveness of reinforcement of polymers using rigid particles depends on the mechanical properties and shape of inclusions, the level of the interfacial (adhesion) interaction, the geometry of distribution of inclusions in matrix. In principle, self-consistent analytic approaches of composite mechanics are applicable for predicting hardening of polymer reinforced by rigid particles of highly asymmetric shape. However, such methods are based on the Eshelby’s solution of the problem of deformation of uniformly loaded at infinity elastic medium with a single ellipsoidal inclusion, suggest preservation of the shape of inclusions and do not include details of the interaction of the filler particles. The main objective of this work is to evaluate the influence of initial curvature of the carbon nanotube (CNT) on the effective elastic moduli of CNT/polymer composites. Mechanical properties of polymer matrix and CNT are described in the framework of isotropic theory of elasticity. CNT is modeled using volumetric curved elastic rod. The ratios of Young's modulus of CNT and matrix were 10-1000. Poisson's ratio of CNT and matrix materials assumed to be equal 0.33. Interphase connectivity assumed to be ideal. Effective elastic moduli of composites were calculated using the theory of averaging based on the numerical solution of the finite element method and the super-elements method of relevant 3D boundary value problems of the theory of elasticity. There were considered representative volume elements (the periodicity cell) containing both single inclusions with varying degrees of curvature and aspect ratios and randomly oriented periodically arranged inclusions. As a result of these calculations, numerical estimates of the effective stiffness of curved CNTs were obtained. It is shown that increasing of the curvature of CNT results in a reduction of the longitudinal rigidity and an increase of the Poisson's ratio of composite in plane containing CNT. The developed models provide a quantitative estimate of the polymer composite stiffness change with different combinations of parameters of reinforcing bars - the elastic characteristics, curvature, aspect ratio, their distribution over the volume of the polymer matrix.
O-81 SIZE, SHAPES AND SUPERSTRUCTURES OF NANOMATERIALS WITH XENOCS SAXS/WAXS INSTRUMENT
F. Bossan, P. Panine, S. Rodrigues, M. Fernandez-Martinez, P. Hoghoj, R. Mahe, N. Galatanu
Xenocs, Sassenage, France [email protected]
Nanostructured materials hold major expectations but understanding their properties requires the investigation of a large number of compositions or process combinations necessitating characterization requirements over broad length scales. Moreover new materials based on a bottom up approach, i.e. self-assembly of complex materials as such as block copolymer are of significant interest for a wide range of applications but still require control and understanding of their morphology, both for fundamental studies or for routine quality verification.
Small Angle X-ray Scattering (SAXS) is a powerful measuring method for investigating nanostructured materials providing information in the range from 1 nm to beyond 150 nm such as nanoscale morphology, mesoscale phase identification, surface to volume ratio of internal structures as few examples. The method requires little sample preparation, is non-destructive and in contrast to microscopy probes a large volume of the sample enabling a statistically meaningful result. However, the same technique can be applied to surface only in the so-called “grazing incidence geometry”. When combined with Wide Angle X-ray Scattering (WAXS) one can also get information on crystalline structure. Major developments in components and subassemblies achieved the past years offer capabilities for fast routine measurements, screening process parameters or samples. Moreover, most of the time such experiment can be conducted with sample maintained in normal atmospheric conditions, without further preparation, enabling a simplified access to the nanostructure information. Wet or solvent containing samples can then be easily studied.
This presentation will summarize latest Xenocs developments on SAXS/WAXS instrumentation emphasizing impact for nanomaterials characterization. Capability to measure simultaneously nanoscale structure and crystalline features during in-situ studies such as temperature controlled measurements will be highlighted. Also high throughput characterization of microinjected semicrystalline polymers will be shown emphasizing the nanostructure and processing relationships. Finally GISAXS measurements on block copolymers will be shown as an example of characterization of self-assembled structures.
POSTER PRESENTATIONS
P-001 THE DEPENDENCE OF MOLECULAR CHARACTERISTICS OF HYPERBRANCHED POLYMETHYLSILSESQUIOXANES ON THEIR
STRUCTURE AND COMPOSITION
O.V. Golub1, A.I. Amirova1, I.B. Meshkov2, D.A. Migulin2, A.M. Muzafarov2, A.P. Filippov1 1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, St. Petersburg, Russia
2 - N.S. Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, Moscow, Russia [email protected]
The work is dedicated to investigation of molecular and hydrodynamic properties of series of hyperbranched polymethylsilsesquioxanes (PMSQ).
In order to obtain the samples different in molecular-weight and structure characteristics, the condensation time was varied [1]. The hydrodynamic, optical, and molecular properties of PMSQ are discussed. The experiments were carried out by the static and dynamic light scattering, viscometry, densimetry, and refractometry in toluene. It was found out the correlation between the duration of polycondensation and the values of weight-average molar mass, intrinsic viscosity, and hydrodynamic radius of macromolecules. Moreover, since the condensation promotes the formation of cycles into the macromolecules, the increasing of reaction time leads to the growth of intramolecular density. In particular, the change of ration of methylsilsesquioxane monomer units to trimethylsiloxane ones from 1: 2 to 1: 3.4 is in agreement with the decrease of specific partial volume values. In the same way, the magnitudes of refractive index increment correlate with the polymer composition. [1] I.B. Meshkov, A.M. Muzafarov. Synthesis of hyperbranched polymethylsilsesquioxanes. 9th International Workshop on Silicon-based Polymers. Moscow, September 22-25, 2013. The work was supported by project MK-222.2014.3.
P-002 A THEORY OF CHROMATOGRAPHY OF SEMI-CYCLIC POLYMERS: SIZE EXCLUSION AND THE CRITICAL ADSORPTION
POINT
A.A. Gorbunov, A.V. Vakhrushev Institute for Highly Pure Biopreparations, St. Petersburg, Russia
Liquid chromatography is a powerful tool for the separation and analysis of topologically different polymers. In particular, it is well known that both size-exclusion chromatography (SEC) and especially liquid chromatography at the critical adsorption point (CAP) can be used to separate linear and ring-shaped polymers. Here we are discussing main features of the chromatographic behavior of semi-cyclic polymers consisting of linear (L) and ring (R) fragments. In particular, tadpole-shaped (RL) and manacle-shaped (RLR) polymers are considered in much detail, as well as other relevant polymers (LRL, RLRLR, etc.). We present the results of an ideal-chain theory of chromatography of such polymers at both SEC and CAP conditions. According to the theory, the SEC-behavior of all these polymers is very similar, being slightly different only in the quantitative aspect. Unlike SEC, the predicted CAP-behaviors are strongly dependent on the chain architecture. Moreover, as it follows from the theory, the dependences of the chromatographic partition coefficient of such macromolecules on the lengths of linear and cyclic parts are qualitatively different. This offers a number of new interesting opportunities for the chromatographic analysis. By using the theory and by simulating ‘theoretical’ chromatograms, we predict possibilities to fully separate polydisperse RL-polymers from its cyclic and linear precursors, to discriminate between symmetric and asymmetric RLR structures, as well as to fractionate semi-cyclic polymers by molar mass of its cyclic parts and by the number of cycles.
P-003 AGGREGATIVE PROPERTIES OF N-VINYLPYRROLIDONE AND 2-AMINOETHYL METHACRYLATE HYDROCHLORIDE COPOLYMERS
IN DILUTE SOLUTIONS
E.B. Tarabukina, N.V. Zakharova, M.V. Solovskij, T.A. Prazdnikova Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia
Statistical copolymers of N-vinylpyrrolidone (VP) and 2-aminoethyl methacrylate (AEM) are prospective as drug carriers due to their water solubility, non-toxisity, and availability in their composition of functional aminogroups able to bind a biologically active compound (drug). In this respect a study of the behaviour of these copolymers in water solutions of different acidity is necessary for the target control of drug delivery. The VP-AEM copolymers in the hydrochloride form with different AEM content were investigated in buffer 0.1 n AcNa water solutions using the method of dynamic light scattering. pH of the solutions was tuned by adding HCl or NaOH. Molar masses were obtained by means of sedimentation and diffusion analysis. Aggregative structures that are conditioned by hydrophobic fragments in functional AEM units were found out in solutions at any concentration or pH. Two modes in size distributions were derived from the dynamic light scattering experiments that are responsible for individual copolymer macromolecules as well for their aggregates. The hydrodynamic size of aggregates decreases with dilution and with the acidity increase. The quantity of aggregates at different pH and concentration is estimated.
P-004 STEREOREGULARITY AND STRUCTURE OF CARDOPOLYMER – POLYMETHYLEDENEPHTALIDE
M.I. Buzin1, A.T. Zdvizhkov2, R.A. Novikov2, G.G. Nikiforova1, A.A. Korlukov1, V.S. Papkov1,
S.N. Salazkin1 1 - Russian Academy Sciences, A.N. Nesmeyanov Organoelementcompounds institute
2 - Russian Academy Sciences N.D. Zelinskii Organic chemistry institute [email protected]
Polymethyledenephtalide (PMPh) is a cardopolymer [1] in which the side cyclic phtalide groups in its macromolcules with the most probable "head to tail" configuration are separated only by one methylene bridge (Fig. 1).
Figure 1
Such a high concentration of the phthalide substituents along the polymer chain leads to considarable steric interactions, which in turn manifest themselves in a certain level of the main chain stereoregularity depending on radical polymerization conditions of methyledenephtalide. The stereochemical structure of PMPh was established by means of NMR spectroscopy on 1H and 13C nuclei using two-dimensional correlation techniques COSY , TOCSY, NOESY, DOSY, editing - HSQC, and HMBC. Also the full assignment of the observed signals with a respect to stereochemistry was made. It was shown that the radical bulk polymerization initiated by peroxides results in formation of a polymer enriched by syndio - triads. The introduction into the reaction medium solvents of different nature affects the stereoregularity of the resulting polymer. Thus, PMPh obtained in cyclohexanone is an atactic polymer whereas in less polar m-cresol an isotactic structure is realized. PMPh synthesized in bulk and cyclohexanone or m-cresol solutions is able to crystallize partially forming ordered regions of very small sizes judging from the half-width of the crystalline peaks in X-ray diffractograms. The dependence of the crystalline structure on the content of syndio- or iso- triads in the polymer, as well as on samples history was observed. The glass transition temperature of PMPh is 295oC, and the melting temperature of the crystalline phase is above its decomposition temperature (320oC). 1. S.V. Vinogradova , Y. S. Vygodskii. Cardopolymers (Loop Polymers). Russ. Chem. Rev.1973. V.42. No 7. P.551- 559. This work was supported by RFBR (Grant #12-03-00915).
P-005 MOLECULAR MOBILITY AND DIELECTRIC RELAXATION IN MULTIBLOCK (SEGMENTED) COPOLYURETHANE IMIDES
N.A. Nikonorova1, A.L. Didenko1, V.V. Kudryavtsev1, D.A. Zhuravlev2, R.A. Castro2 1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, Saint-Petersburg, Russia
2 - Herzen State Pedagogical University of Russia, Saint-Petersburg, Russia [email protected]
Segmented copolymers consist of thermodynamically incompatible rigid and flexible blocks (segments) of different nature, which causes the microheterogeneity of such systems. Segmented copolymers are characterized by an extended plateau of high elasticity, the interval which extends from the glass transition temperature, Tc, of flexible component (matrix) to the softening or melting of the hard component (domains). In this work we present the dielectric behavior of the segmented copolymers, including units of aromatic urethane imide (hard component) and aliphatic polyester (flexible component). As initial monomers, pyromellitic anhydride, 1,4-bis(4'-aminophenoxy)diphenylsulfone and poly(ethylene adipate) (Mn = 2700), terminated with 2,4-tolylenediisocyanate were used.
O
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CH3
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O CH2 CH2N
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CH3
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(CH2)4
Dielectric spectra were obtained on a broadband dielectric spectrometer "Novocontrol" (concept 41) with automatic frequency analyzer ALPHA-ANB. In the investigated temperature (–100 – +2300С) and frequency (10-2 – 107 Гц) intervals, the dependences of // = (f) show three regions of dielectric absorption, the molecular mechanisms which are due to the local mobility of the polar groups adjacent to the flexible block (-process) and of the polar groups disposed between the phenyl rings (-process), and due to molecular motion of segments of the flexible block (α-process). The most probable relaxation time, max, was determined by empirical Havriliak-Negami equation, HN,
n
k HN
k
kk
ki1 )(1
Im)(
. At temperatures above Tc, the contribution to // caused
by a conductivity takes into account. For the α-relaxation the frequency dependences of // reliably described by a single HN process plus a contribution due to conductivity. At low temperatures, the dielectric spectra are well approximated by the sum of two HN processes: the - and -relaxations. Dependences of –�lоgmax� = (1/T) in the ranges of the - and -processes are linear, which is typical of local forms of molecular mobility, and described by the Arrhenius
equation,
RT
ET aexp)( 0max , with the values of –lоg0 и Еа equal to 15.8 and 9.2 kcal/mol, and 18.2
and 14.4 kcal/mol, respectively. For the α-process, the dependence of –�lоgmax = (1/T) is nonlinear, which is characteristic of cooperative forms of molecular mobility, and is described by Vogel-Fulcher-Tamman-Hesse
equation,
0
0max expTT
B , with the values of the parameters –�lоg0, В и Т0 equal to 7.9, 1499,
and 186 K, respectively. Tc determined by extrapolation of the –�lоgmax = (1/T) dependence for the α- process to lоgmax=0 (max = 1 с) is equal to �–50С. At a temperature 2000С a sharp increase (by two orders of value) in the relaxation time takes place. Atthe same temperature the conductivity increases from 410-9 up 110-5 S/m. This fact may be due to structural changes, such as melting domains containing rigid moieties or morphological transformations. Thus, the plateau of high elasticity for the studied segmented copolymers, defined by the dielectric method, is in the range from �5 up 2000С.
P-006 STRUCTURE-PROPERTIES RELATIONS OF POLYLYSINE DENDRIGRAFTS: EXPERIMENT AND COMPUTER SIMULATION DATA
N.P. Yevlampieva1, B.M. Okrugin1, I.M. Neelov2,3
1 - Saint Petersburg State University, Physics Faculty, Ulianovskaja st. 3, 198504 Saint-Petersburg, Russia 2 - ITMO University, St.Petersburg, Russia
3 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St.Petersburg, Russia [email protected]
Scientific interest to polymers of dendritic architecture is significantly increased with the development of modern nano- and bio-technologies. Dendrimers have a number of advantages if compared to the linear structure polymers. Dendritic architecture allows to controlling the topology, volume, form, sizes and surface properties of the macromolecules. One of the modern trends in this field a synthesis of dendritic analogues of well known polymers can be named. This is connected with a possibility to realize more careful control of the properties on the level of individual molecules. The tendencies marked are as well typical for polymeric derivatives of lysine that are widely used in modern medicine, pharmacology, cosmetology and various biotechnologies. Not far ago the synthesis of dendrigraft polylysines was developed and improved [1]. Dendgrigrafts represent a relatively new class of dendritic molecules attractive due to more simple and cheap way of theirs synthesis if compared to dendrimers. The present work summarizes results of the experimental research on hydrodynamic properties of poly-L-lysine dendrigrafts (DPL) in different solvents [2, 3] and computer simulation data on these molecules at the variable ionic strength value. The hydrodynamic behavior of DPL molecules is analyzed in comparison to the polylysine dendrimers and other water-soluble dendrimers of the similar structure. It was detected that in contrast to dendrimers the size of polylysine dendrigrafts substantially depend on the solvent properties. [1] Collet H., Souaid E., H. Cottet et al. // Chem. Eur. J. 2010, 16, 2309 – 2316. [2] Yevalmpieva N., Dobrodumov A., Nazarova O., Okatova O., Cottet H. // Polymers. 2012. V. 4. N 1. P. 20-31. [3] Yevalmpieva N., Dobrodumov A., Okatova O., Cottet H. // Saint Petersburg State University Bulletien. 2011. Series. 4. N. 4. С. 131-138. Research was performed using the resources of RC "Computer Center" of St. Petersburg State University
P-007 ORIENTATION PROPERTIES OF SEMIFLEXIBLE DENDRIMERS AND THEIR MANIFESTATION IN NMR SPIN-LATTICE RELAXATION
D.A. Markelov1, M. Dolgushev2, Yu.Ya. Gotlib1, A. Blumen2
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences St. Petersburg, Russia 2 - Theoretical Polymer Physics, University of Freiburg, Freiburg, Germany
We investigate the orientation properties of labelled segments in semiflexible dendrimers of different generation numbers (G = 2,...,7). For this we use the semiflexible Gaussian viscoelastic model introduced in Ref. [1]. Here we confront the results obtained for semiflexible dendrimers to those for flexible ones. We find - as in the flexible case - that the orientation autocorrelation function of each segment, M1(t), depends mainly on the length of the branch which emanates from that segment. In other words, M1(t) depends very strongly on m, the topological distance of that particular segment from the dendrimer’s periphery. However, semiflexibility leads to an increase of the contribution of long-scale motions to M1(t). The obtained results were used in the calculation of the frequency dependence of the spin-lattice relaxation time, T1(ω). The procedure made use of the spectral density J(ω), which is the real part of the Fourier transformed P2(t) autocorrelation function. We also used the approximation P2(t) ≈ M1
3(t). We found, in contrast to flexible dendrimers [2], that the 1/T1(ω) maximum is determined by the maximal relaxation time of the labelled branch and, as a result, depends on m, i.e. on the location of the labelled segment and on the size of the dendrimer. This conclusion is confirmed by a number of NMR experiments [3-5].
The authors acknowledge support through the Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Program SPIDER (PIRSES-GA-2011-295302). [1] M. Dolgushev and A. Blumen, J. Chem. Phys., 131, 044905 (2009). [2] Yu. Ya. Gotlib and D. A. Markelov, Polymer Sci. Ser. A., 49, 1137 (2007). [3] C. Malveau, W. E. Baille, X. X. Zhu, and W. T. Ford, J. Polym. Sci., Part B: Polym. Phys. 41, 2969 (2003). [4] D. A. Markelov, V. V. Matveev, P. Ingman, M. N. Nikolaeva, E. Lahderanta, V. A. Shevelev, and N. I. Boiko, J. Phys. Chem. B 114, 4159 (2010). [5] L.F. Pinto, J. Correa, M. Martin-Pastor, and R. Riguera, J. Am. Chem. Soc. 135, 1972 (2013).
P-008 EFFECT OF DEGREE AND REGULARITY OF BRANCHING ON HYDRODYNAMIC PROPERTIES OF HYPERBRANCHED
POLYCARBOSILANE
T.U. Kirila1, A.I. Amirova1, N.A. Sheremeteva2, A.M. Muzafarov2, A.P. Filippov1 1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, St. Petersburg, Russia
2 - N.S. Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, Moscow, Russia [email protected]
The twenty years of investigations of hyperbranched polymers (HBP) and dendrimers allow to find out the rather clear relationship between molecular properties and molar masses (MM), degree of branching (DB), and spacer’s length. However, the influence of a distribution of branching points or regularity of branching is not revealed. The purpose of our work was to study the role of the regularity and the degree of branching in hydrodynamic behavior of HBP. The object investigated was carbosilane pseudo-dendrimer produced by two steps. At first stage, the hyperbranched poly(diallyl carbosilane) with DB = 50% was synthesized [1]. At second stage, it was modificated in way that all linear monomer units became the dendritic ones [2]. The resulting irregular HBP was called as pseudo-dendrimer because it DB is equal to 100%, as this for “perfect” dendrimers. It is needed to mark, the monomer unit composition of polymer prepared is identical to that of carbosilane dendrimer with butyl terminal groups [3]. The experiments were carried out by the molecular hydrodynamic and optic methods. The five fractions within wide range of MM (from 5000 up to 450000) were investigated in hexane and toluene solutions. Mark-Kuhn-Howink dependences for intrinsic viscosity and hydrodynamic dimensions were obtained. It is shown that toluene is poorer solvent to carbosilane pseudo-dendrimer then hexane. This was based on the reducing of the second virial coefficient values and intrinsic viscosities. Despite of this fact, the slopes of Mark-Kuhn-Howink dependences coincided in both solvents. The effect of branching regularity was determined by comparison of hydrodynamic properties of studied pseudo-dendrimer and those of its analogs – initial poly(diallyl carbosilane) [1] and carbosilane dendrimer [3]. The analysis of molar-mass dependences of intrinsic viscosity and macromolecule size allowed to conclude that, in terms of hydrodynamic behavior, carbosilane pseudo-dendrimer is close to initial hyperbranched polycarbosilane [1] and differ dramatically from dendrimer [3]. In other words, hydrodynamic properties of HBP are defined by the branching regularity mainly while DB increasing from 50% to 100% does not change significantly the hydrodynamic characteristics. 1. E.B. Tarabukina, et al. Polym. Sci. A, 2006, 48, 974. 2. A.P. Filippov, et al. Macromol. Symp., 2012, 316, 43. 3. E.A. Tatarinova, et al. Russ. Chem. Bull., 2004, 53, 2591.
P-009 CONFORMATION MACROMOLECULES ОF THE LINEAR-DENDRITIC DIBLOCK COPOLYMERS OF HYPERBRANCHED
POLYPHENYLENGERMAN AND LINEAR POLYMETHYL METHACRYLATE
M.A. Simonova1, O.G. Zamyshlyayeva2, Yu. D. Semchikov2, A.P. Filippov1
1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, St-Petersburg, Russia 2 - Lobachevski Nizhny Novgorod State University, Nizhny Novgorod, Russia
At presents, the linear-dendritic diblock copolymers are at the focus of considerable attention of researches due to the possibility to regulate their properties varying the chemical structure and molar mass characteristics of components. The hybrid macromolecules containing fluorine fragments are important because of the inclusion of such groups into macromolecules leads to high selectivity of polymer to solvents. Consequently, there is special interest in investigating the behavior of these copolymers in solutions. The aim of this work is to investigate the properties of the individual macromolecules of the hybrid linear-dendritic block-copolymers PPG-PMMA of hyperbranched perfluorinated polyphenylenegermane (PPG) and linear polymethylmethacrylate (PMMA). For comparison, the model functionalized polymers PMMA-Ge(C6F5)3, i.e. linear PMMA with the terminal -Ge(C6F5)3 groups, were investigated. The polymers were studied by the methods of molecular hydrodynamics and optics in dilute solutions in chloroform which is a good solvent for PMMA and -solvent for PPG. The solution behavior of model polymers PMMA-Ge(C6F5)3 is practically the same as for chain PMMA molecules. Correspondingly, the existence of massive -Ge(C6F5)3 groups on the chain ends does not lead to change in hydrodynamic and conformational properties of PMMA. Another situation is for hybrid linear-dendritic PPG-PMMA diblock copolymers. Their macromolecules have a more compact and dense structure in solution in comparison with linear PMMA. The analysis of obtained experimental results makes it possible to conclude that for investigated copolymers, the “encapsulated hyperbranched block” conformation is realized: the hyperbranched PPG block is well screened by PMMA chain. This work was supported by MK – 222.2014.3
P-010 ALIPHATIC GROUP INFLUENCE ON HYDRODYNAMIC PROPERTIES OF RIGID POLY(PHENYLENE) PYRIDINE-CONTAINING
DENDRONS
N.V. Tsvetkov1, A.S. Gubarev1, A.A. Lezov1, L.I. Akhmadeeva1, N.V. Kuchkina2, Z.B. Shifrina2 1 - Department of Physics SPbSU,Saint-Petersburg, Russia
2 - Nesmeyanov Institute of Organoelement Compounds, Moscow, Russian [email protected]
Dendrimers remain the system of great interest as there are a numerous structure possibilities in molecule building with particular features of their highly branched but symmetrical architectures and their relatively precise molecular structures[1,2]. On the other hand there are obvious prospects in their applications: dendrimers are capable of encapsulating diverse agents, thus creating possibilities for their wide use in medicine and pharmacology[2]. Along with the majority of studies devoted to characterization of branched macromolecules with rather flexible matrices the system under study: poly(phenylene) pyridine-containing dendrons is built with rigid phenylene and pyridine rings and this suggests quite rigid oblate structures[3]. The set of hydrodynamic methods (viscometry, veolocity sedimentation and translation diffusion) were used to study the peculiarity of hydrodynamic behavior of poly(phenylene) pyridine-containing dendrons of third generation in benzene solutions possessing aliphatic end groups and lacking ones. The hydrodynamic parameters: intrinsic viscosity, sedimentation and diffusion coefficients were acquired for this system as well as molecular masses were compared with theoretical estimates. Thorough analysis of dendron conformations and their hydrodynamic characteristics have been carried out.
N
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Fig. Objects under study: structural representation of poly(phenylene) pyridine-containing dendrons - core and one possessing aliphatic end-groups.
[1] Wang, H.; Zheng, L. F.; Peng, C.; Guo, R.; Shen, M. W.; Shi, X. Y.; Zhang, G. X. Computed tomography imaging of cancer cells using acetylated dendrimer-entrapped gold nanoparticles. Biomaterials 2011, 32, (11), 2979-2988. [2] Pavlov, G. M.; Korneeva, E. V.; Jumel, K.; Harding, S. E.; Meijer, E. W.; Peerlings, H. W. I.; Stoddart, J. F.; Nepogodiev, S. A. Hydrodynamic properties of carbohydrate-coated dendrimers. Carbohydr. Polym. 1999, 38, (3), 195-202. [3] Tsvetkov, N. V.; Filippov, S. K.; Kudryavtseva, T. M.; Ivanova, V. O.; Shifrina, Z. B.; Averina, M. S.; Firsova, N. V.; Rusanov, A. L. Hydrodynamic properties of rigid pyridine-containing poly(phenylene) dendrimers in solutions. Polym. Sci. A 2006, 48, (4), 450-455. This work was supported by the Russian Foundation for Basic Research (projects number 12-03-00687 and 14-03-31861).
P-011 ELECTROOPTICAL AND SPECTRAL PROPERTIES OF 9, 9-DI-N-OCTYLFLUORENE AND 2, 1, 3-BENZOTHIADIAZOLE COPOLYMERS IN
SOLUTION
N.P. Yevlampieva1, A.P. Khurchak1, G.I. Nosova2, R.Yu. Smyslov2, I.A. Berezin2, A.V. Yakimansky2
1 - St. Petersburg State University, Physics Faculty 2 - Institute of Macromolecular Compounds, RAS
Conjugated copolymers with the different structure chromophore units have attracted a great attention of researches in the past decades due to their applications in a number of molecular optoelectronic devices such as organic light emitting diodes, organic field effect transistors, thin film sensors, and photovoltaic devices. A majority of publications on physical properties of conjugated polymers are based on studies of such materials made in bulk films. However, the inherent disorder present in macromolecular thin films can often mask fundamental electronic properties of polymer. At the present work we demonstrate that investigation of solution properties of copolyfluorenes may be very useful for a fine tuning of its emission properties in film. Polyfluorene derivatives are the object of interest in molecular electronics as perspective materials for development of efficient white light emitting diodes. With this purpose, green- and red-emitting fragments are covalently inserted into a blue-emitting polyfluorene chain. A strong effect of the microstructure of copolyfluorenes on their luminescence spectral parameters is one of the problems to be solved in the field of molecular electronics. To clarify this issue, in the present study we have compared two copolymers of 9,9-di-n-octylfluorene (DOF) and 2,1,3-benzothiadiazole (BTD) synthesized Suzuki [1] and Yamamoto [2] polycondensation reactions. The concentration of BTD comonomer units in poly-DOF chains was small (~1 mol %). Molecular properties of copolymers have been investigated by electrooptical Kerr effect method. Absorbance and fluorescence emissions of copolymers have been characterized in solution. The conjugation length parameter for DOF-BTD copolymers (35 Å) was estimated based on electrooptical properties as the length of kinetic fragment of their chain. Both studied copolymers displayed similarity in molecular and absorption properties, but the fluorescence spectroscopy clearly shown an existence of microstructural specificity in DOF-BTD chains. The following conclusions have been made on the microstructure and emission properties of the studied DOF–BTD copolymers: a) Yamamoto reaction leads to formation of BTD-blocks, while Suzuki reaction leads to isolated and randomly distributed BTD-units along the copolymer chains; b) Quantity of junction points between DOF- and BTD-units is responsible for observation of energy transfer from DOF to BTD-units for copolymers in solution by fluorescence spectroscopy; c) Films of DOF–BTD copolymers synthesized by Suzuki/Yamamoto reactions will have different emission properties because of BTD-block and isolated BTD-unit absorbance bands are shifted relative to each other; d) DOF–BTD copolymer of a microblock structure obtained by Yamamoto reaction is preferable as the material for white light emission devices since that type macromolecular microstructure leads to an efficient spreading of the luminescence spectrum of the host polymer over the visible range towards red emission light. The work is supported by the Scientific Program of the Presidium of the Russian Academy of Sciences “Polyfunctional materials for molecular electronics” (coordinator – academician S.M. Aldoshin). [1] Miyaura N., Suzuki A. // Chem. Rev. 1995. V. 95. № 7. P. 2457. [2] Yamamoto T, Ito T, Kubota K. // Chem. Lett. 1988. V. 17. P. 153.
P-012 SEPARATION OF DI- AND TRIBLOCK COPOLYMERS IN LIQUID ADSORPTION CHROMATOGRAPHY. SIMULATION AND EXPERIMENT
A.A. Gorbunov1, B. Trathnigg2
1 - Institute for Highly Pure Biopreparations, St. Petersburg, Russia 2 - Central Polymer Lab–Molecular Characteristics (CePOL/MC), Graz, Austria
By using theory and simulation we have analyzed possibilities and conditions for the chromatographic separation of copolymers of different architecture: diblocks AB, symmetric and asymmetric triblocks ABA. In high molar mass copolymers, if blocks A are monodisperse and strongly adsorbable, different block structures can be discriminated at the critical adsorption point (CAP) and at the size-exclusion (SEC) conditions for B. The SEC mode for B is appropriate for copolymers with homogeneous or moderately heterogeneous blocks B; better separations are expected in wide pores. For the copolymers with very heterogeneous blocks B the better option is the CAP mode for B and narrow-pore adsorbents. A separation of low molar mass copolymers ABA and AB can be also achieved by liquid chromatography, if the outer blocks elute in the adsorption mode, and the center block is uniform and elutes at the CAP or in the SEC range. Under these conditions, even a separation according to symmetry can be achieved. This behavior, which is predicted by the theory, is verified by the experiment: simulated and experimental chromatograms for block copolymers of ethylene oxide and -caprolactone are in a good qualitative agreement.
P-013 MULTIBLOCK (SEGMENTED) POLY(URETHANE IMIDE)S. SYNTHESIS AND DYNAMIC MECHANICAL PROPERTIES
A.L. Didenko, V.E. Smirnova, V.M. Svetlichny, V.E. Yudin, V.Yu. Elokhovskii, I.V. Gofman,
E.N. Popova, V.V. Kudryavtsev Institution of Russian Academy of Sciences, Institute of Macromolecular Compounds RAS, 199004, Russia,
St.Petersburg, Bolshoi pr.VO, 31 [email protected]
Poly(propylene oxide), poly(ethylene adipate) and poly(1,6-hexane diol/neopentile glycol-alt-adipic acid) terminated all 2,4-toluylene diisocyanate have been used for synthesis of segmented poly(urethane- imide)s. Anhydride terminated poly(ether/ester) prepolymers were prepared by the reactions of the above macromonomers with 1,3-bis(3',4-dicarboxyphenoxy)benzene dianhydride. Each prepolymer hes reacted with 1,4-bis(4'-aminophenoxy)diphenylsulphone, giving a poly(urethane-imide). Hydroxy terminated poly(1,6-hexane diol/neopentile glycol-alt-adipic acid) has been used in the preparation of the poly(ester-alt-ether-imide) also. In this case, the anhydride terminated poly(ester-alt-ether) prepolymer prepared by the reaction of poly(1,6-hexane diol/neopentile glycol-alt-adipic acid) with 1,3-bis(3',4-dicarboxyphenoxy)benzene dianhydride reacted with 1,4-bis(4'-aminophenoxy)diphenylsulphone, giving the poly(ester-alt-ether-imide) . All copolymers form a strong elastic film. Thermal analysis data indicate that the copolymers synthesized were stable up to 3200C. From the DSC and DMTA data, all copolymers have a low glass transition temperature (- 500C up to 00C).In all cases, there is the elastic rubbery plateau in the temperature dependences range 0-200 oC. These copolymers display also a very low factor (tan δ), suggesting excellent dynamic properties. An extension of a rubbery plateau to elevated temperatures was observed for a poly(urethane-imide) composition with a silicon resin. Above 2000C polymers went into a flowable state. The polymers synthesized behave as thermoplastic elastomers.
P-014 INTERNAL POLYMER DYNAMICS: SIMULATIONS VERSUS EXPERIMENTS
J. Kubecka, P. Kosovan
Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Czech Republic
Internal polymer dynamics has been studied by fluorescence correlation spectroscopy, FCS, in single-molecule experiments. The results have been analyzed in terms of the mean squared displacement, MSD. It was obtained by inversion of the fluorescence intensity autocorrelation function, G(t), which is the quantity directly measured in FCS experiments. We present a simulation study, where we compare the MSD obtained from the simulation trajectory with the apparent MSD obtained from the inversion of G(t) from the same simulation. We investigate the applicability of the inversion in different situations, and the statistical error of the obtained apparent MSD, and its impact on the evaluation of experimental data.
P-015 TEMPERATURE DEPENDENCE OF THE INTRINSIC VISCOSITY OF POLY(METHYL METHACRYLATE) IN BINARY SOLVENTS USED AS
ELUENTS FOR LIQUID CHROMATOGRAPHY UNDER CRITICAL CONDITIONS
N.G. Belnikevich, L.S. Litvinova, Z.F. Zoolshoev
Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia [email protected]
In recent years, a surge in interest has been observed in the adsorption chromatography of polymers and adsorption chromatography under critical conditions as a method complementary to exclusion chromatography for studying various types of structural and topological inhomogeneities of synthetic polymers and composites. Separation at the critical adsorption point requires very thorough control over chromatographic conditions, such as characteristics of the stationary phase and the composition and temperature of the mobile phase. In our preceding measurements it was revealed that the thermodynamic quality of a solvent affects the chromatographic behavior of PS and PMMA under critical conditions of adsorption chromatography, It was shown experimentally that binary solvents used as mobile phases are mostly thermodynamically good solvents. However, changes in intermolecular interactions with temperature are expectable The intrinsic viscosity [η]. was employed in this study to evaluate the thermodynamic quality of binary solvents. It is known that [η] is directly proportional to the volume of a random coil and the degree of swelling of a macromolecular coil α3 соответственно. The intrinsic viscosity values of PMMA with М w = 35 × 104 and a polydispersity index of Мw/Мn < 1.2 were measured in binary solvents that were used as eluents in chromatographic experiments and that contained THF, MEK, or the θ solvent acetonitrile as displacers and adsorption inactive solvents such as dichloromethane (DCM), dichloroethane (DCE), chloroform, toluene, carbon tetrachloride, and cyclohexane (CH). The experiments were conducted in the temperature range 15–40°С ±0.05°C. For all above listed binary systems compositions corresponding the critical conditions of adsorption chromatography were experimentally determined and the temperature dependences of [η] were experimentally obtained. The values of [η] and α3 indicate that all binary solvents are good solvents for PMMA, regardless of temperature. The degrees of swelling of macromolecular coils in them change from 3.9 to 2.9. Almost all dependences of [η] (α3) – Т0С are nonlinear. The scatter in the [η] values with variation in temperature is 5% at most. It follows that the temperature dependence of [η] (α3) is very weak for any composition of the solvent. Even solvents containing acetonitrile (the θ solvent) behave as good solvents at temperatures below the θ point. α3 remains close to 3 throughout the studied temperature range. This implies that the observed insignificant changes of the molecular characteristics of PMMA cannot make a considerable contribution to the temperature dependence of retention characteristics.
P-016 CURRENT AND SUPERCURRENT THROUGH FILMS OF DIELECTRIC POLYMERS
A.N. Ionov1, M.N. Nikolaeva2, A.A. Martynenkov2
1 - Ioffe Physico-Technical Institute, Russian Academy of Sciences, St.-Petersburg, Russia 2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St.-Petersburg, Russia
The temperature dependences of the resistivity of thin films of different polymer dielectrics (e.g., polystyrene, polysiloxaneimide, atactic polypropylene, polyamidine, galactomannan polysaccharide) have been obtained. The investigated films exhibit metallic type of conductivity in Metal-Polymer-Metal (M-P-M) sandwich structures. At temperatures of liquid helium through the Superconductor-Polymer-Superconductor structures supercurrent may flow. At low temperatures were also investigated the effect of transverse magnetic field on the conductivity of the conductive polymer channels in polyamidine. The thickness of the polymer films in the sandwich structures was about one micrometer. Conducting channels in the dielectric polymer matrices were created in M-P-M sandwich structures due to the effect of polymer electrification by metal substrate [1-3]. Characteristic feature of the M-P-M structures was the supercurrent in polymer channels when the metal electrodes are in the superconducting state. We observed that in the structures of Sn-Polyamidine-Sn the supercurrent is suppressed at the magnetic field H < Hc(Sn) (here Hc(Sn) is a critical field of Sn at fixed temperature). It means that effect is related to polymer channels. 1. Rentzsch R., Ionov A.N., Nikolaeva M.N., Dunaevskii M.S. Phys Stat Sol (c). 2006, 3, 275-279. 2. Ionov A.N., Nikolaeva M.N., R.Rentzsch. JETP Letters. 2007, 85, 636-638 3. Nikolaeva M.N., Aleksandrova G.P., Martynenkov A.A., Rus. J. Phys.Chem (A). 2012, 86, 812-815. The work is supported by RFBR grant № 13-03-00747.
P-017 LIVINING CATIONIC POLYMERIZATION OF 2-ETHYL-2-OXAZOLINEINITIATED WITH TOSYL HALOGENIDES
A.V. Tenkovtsev, A.B. Razina, M.P. Kurlykin
Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia [email protected]
Kinetic investigations on the cationic ring-opening polymerization of 2-ethyl-2-oxazoline were carried out with the use of p-toluenesulfonyl fluoride, p-toluenesulfonyl chloride and p-toluenesulfonyl bromide as initiators. Apparent rate constants of the chain growth and activation energies were determined. The polymerization was shown to be consisted of fast reaction of the p-toluenesulfonic acid chloride or bromide with the oxazoline and rather slow chain growth. When tosyl fluoride is used as an initiator the first step is slow although the apparent propagation rate constant is nearly equal to what was found while polymerization on tosyl bromide and chloride. Comprising the rates of polymerization initiated by tosyl halogenide and N-(2-halogenethyl)-N-tosylpropionamide as well as competitive experiments show that the polymerization of the oxazoline initiated by tosyl halogenides proceeds preferably via ionic active species
Table 1. Apparent polymerization rates (in lmol-1s-1) at different temperatures and activation energies for the initiators under investigation
Initiator 70 0C 80 0C 90 0C 100 0C Ea kcalmol-1 TsF 1.1 10-5 1.2 10-4 3.810-4 1.410-3 30 TsCl 4.210-5 2.010-4 5.310-4 9.110-4 25 TsBr 2.910-4 6.010-4 1.310-3 1.010-3 22
0,0 0,5 1,0 1,5 2,0 2,5 3,00,0
0,2
0,4
0,6
0,8
1,0
1,2
lnM
0/M
t, час
1
2
kapp=6.0 10-4 l mol-1 s-1
kapp=3.1 10-4 l mol-1 s-1
Fig.1 First order kinetic plot for the TsBr (1) and TsBr+2 mol% (CH3)4Br (2) initiated cationic ring-
opening polymerization of 2-ethyl-2-oxazoline in tetrachloroethane at 800C
P-018 SORPTION OF AQUEOUS VAPORS AND COMPATIBILITY IN MIXTURES OF POLY-N-METHYLVINYLACETAMIDE WITH
CARBOXYMETHYLCELLULOSE
L.M. Kalyuzhnaya, I.L. Shevtchuk, A.M. Bochek, M.F. Lebedeva, I.I. Gavrilova, E.F. Panarin IMC RAS
Preparation of polymer mixtures with new functional properties by mixing melts or solutions is one of the methods for obtaining new polymer materials. Hydrophilic cellulose esters are widely used as thickeners, packing materials and etc. Their modification by introduction in polisaccharide of synthetic hydrophilic polymer matrixes such as poly-N-methylvinylacetamide (PMVAA) makes it possible to obtain materials with better physical-mechanical and consumer properties. In this connection the purpose of the present work is to investigate mixtures of PMVAA with carboxymethylcellulose (CMC) with different degree of ionization and to determine compatibility of the mixture components. Nature of interaction of polymer – polymer - water (the general solvent) in triple systems and the water state in a polymer matrix are of great importance. For this purpose sorption of water vapors by mixtures of PMVAA with CMC of different degree of ionization at varied ratio of components (1-99 mass. %) has been studied. To analyze thermodynamic compatibility of polymer mixtures based of sorption data the concentration dependences of Flory-Huggins polymer-solvent interaction parameters χ12 and polymer-polymer interaction parameters 23 were determined. The average size and the amount of solvent associates formed during solvent sorption in polymer matrix were calculated. No additivity of dependence for the water mass uptake on mixture composition for mixtures PMVAA – HCMC and PMVAA-NaCMC was found. Dependence of solubility on composition in triple systems under study was presented in the form of Gibbs-Rozebum triangular phase diagrams. In mixtures of PMVAA with HCMC thermodynamic compatibility of mixture components was observed at 10 - 30 mass.% HCMC. In mixtures of PMVAA with NaCMC thermodynamic compatibility of components was observed at 10 - 20 mass.% PMVAA. Temperature dependences of the storage modulus, the dynamical loss modules and the mechanical loss factor in the films prepared from water solutions of mixtures of different contents based on CMC and PMVAA were investigated. It was determined that at the content of PMVAA in the mixtures NaCMC - PMVAA in the range from 20 to 50% two maxima of mechanical losses were observed that testified incompatibility of components. Similar character of dependences was shown for mixture HCMC-PMVAA that correlated with the sorption data. Nature of interactions of polymer – polymer – water (the general solvent) in triple systems under study was considered, and the state of water absorbed by polymer matrix was analyzed according to Wang - Krevelen method of group contributions and the clustering theory. Peculiarities of thermodynamic compatibility of PMVAA with CMC of different degrees of ionization were related to different processes of forming the mixed system of H-bonds between functional groups at the variation of carboxyl groups amount in CMC.
P-019 CRAZING IN POLYSTYRENE FILMS UNDER DEFORMATIONS BELOW THE CRITICAL VALUES
E.V. Chubarova, M.F. Lebedeva, E.Yu. Melenevskaya, V.V. Shamanin
Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004, St.-Petersburg, Bolshoi pr. 31 [email protected]
By literature data [1], the critical deformation c~0.01 triggers crazing in thin films of glassy polymers with molecular weights exceeding the critical entanglement molecular weight Mc. In our work, crazing was observed under deformations much lower than c. The films were prepared from the polystyrene (PS) samples with strongly different molecular weights obtained by anionic polymerization. Thin films with a thickness of ~30 m were prepared from polymer solutions in various solvents on various substrates by evaporation of solvents. The conditions of craze initiation were studied at various stretch amplitudes and temperatures using standard NETZSCH DMA 242 C for dynamic mechanical analysis (DMA) of film samples. DMA was used for obtaining mechanical characteristics of the samples as well. The molecular weight distributions (MWDs) obtained by size exclusion chromatography of the initial anionic PS samples were compared with those of the films obtained under various conditions and of the films crazed under various conditions. It has been shown that crazing was accompanied by changes in the MWD of the samples, which affected their mechanical characteristics. References 1. Berger, L. L. On the mechanism of craze fibril breakdown in glassy polymers. Macromolecules 1990, v. 23, no. 11, 2926-2934.
P-020 SYNTHESIS AND PHYSICO – CHEMICAL PROPERTIES OF CARBOXYLIC IONITS
M.M. Karimov, E.R. Timerbaeva, M.K. Rustamov, M.G. Mukhamediev
National university of Uzbekistan name after M. Ulugbek, Tashkent, Uzbekistan [email protected]
It is known that carboxyl – containing ionits have a wide using in water – preparation, purification of sewage and also at division and extraction of different biology – active compounds [1,2]. However simplification and improvement of methods of their obtain is one of the main actual problems of chemistry and technology. It is necessary to note that reactions of copolymerization of methacrylic and acrylic acids with different cross – linking reagents are the main methods of their obtain. Numerous investigations have shown that in sorbtion processes of large organic ions, macromolecules and complex inorganic ions only part of carboxylic groups of ionits has participated what has became of base for carrying out of investigations by elaboration of methods of obtain of carboxyl – containing ionits by method of polymer – analogical reactions from large-tonnage polymers. Such accessible components as aminocapronic-antranilic-aminoacetic and aminobentenic acids were used as modificated reagents. Influence of bath module, concentrations of modified reagents, temperature and solvent nature on some physico-chemical properties of synthesized ionits was determined. Synthesized polymeric materials were identified by IR-Spectroscopy and also by method of potenciometrical titration. Statical changing capacity determined by revers titration has reached a value 3.0 mg·ekv/g. Some thermodynamical parameters of reactions of modification were calculated and also influence of nature of modificated reagent was determined. Investigations of stationary and dynamical processes sorbtion – desorbtion have shown an possibility of using of synthesized ionits for softening water and division of some complex organically molecules. Literature 1. Ion – changing materials for processes of hydrometallurgy, purificator of sewage and water preparation. Reference book under red. B.N. Laskorin, M. 1985. P. 40 – 47. 2. Demin A.A., Chernova I.A., Shataev G.K. Ion – changing sorbtion of some biology – active compounds. Sankt – Peterburg, University. 2008. 151p. 3. Papukova K.P. Nikiphirova E.S., Kurchenko V.S. Kuznezov N.P. Influence of solvent nature on the formation of structure and properties of cross – linking polyelectrolyte’s on the base of methacrylic acid and N,N'–ethylendimethacrylamid// J. of appl. Chemistry. 1985. V. 68, N12, P. 2033 – 2038.
P-021 INVESTIGATION OF MOLIBDENIUM SORBTION FROM TECHNOLOGICAL SOLUTIONS
N.M. Rustamova, M.K. Rustamov, M.M. Karimov
National university of Uzbekistan name after M. Ulugbek, Tashkent, Uzbekistan [email protected]
The wide using of sorbtion methods in hydrometallyrgy for concentration of metal ions and also for utilizatation of waste containing toxical components such as ions of heavy metals is connected with construction of large assortiment ion – changing and complex – forming polymeric and materials. The industrial methods for obtaining such ionits are reactions of polymeranalogical conversions of ready polymeric structures. These reaction are difficulted owing to influence of diffusion processes for their carring out and also by multy – stage and labour – consuming character of technological processes of their carrying – out. However the presence of production in our Republic reactionary – able polymers such as nitron and polyvinylchloride has facilitated problem of obtain ion – changing materials by above mentioned reactions. Consequently, using of new anion – changing materials on the base industrial home polymers for elaboration of technology of extraction of rare metals is a very actual task. On department of polymer chemistry of National university of Uzbekistan name after M. Ulugbek during many years new methods of obtaining ion – changing materials have been elaborated on the base of polyacrylonitrile produced by OAO’’ Navoiazot .’’ In results of carrying- out investigations some new anionits with weak and strong – base groups have been obtained. Nitrogen – containing bases – ammonium (MDA – 1) and hexamethylendiamin (MDA-6) were used as modificated reagents. With aim of determination of sorbtion parameters by molibdenium of ionits MDA – 1 and MDA – 6 investigations have been carried out with using mother solutions after sorbtion of renium. The characteristic peculiarity of mother solutions is that in their composition after radium sorbtion molibdenium presented as cations ( MoO2
+2 in composition of neutral molecules of molibdenium sulfate MoO2SO4) anions (complexes of the type (MoO2(SO4)4)
-(2n-2)). This has complicated the sorbtion process of molibdenium from solutions with high acidity. After sorbtion the conditions of desorbtion molibdenium and rhenium from resins containing MDA-1 and MDA-6 were elaborated. On the elaborated model plant and investigations were carried out by sorbtion molibdenium from technological solutions with following compositions: 6,9 g/l Mo; 1,0 mg/l Re; and 3,22 g/l H2SO4. The model plant has consisted from four glass columns by volume 150 ml united by hoses. For carrying-out of investigations by Mo sorbtion samples of sorbents by mass 50 g were transferred in suffer-acidal form. Then every column was filled by moist sorbents which were washed by distilled water. Then on the model plant investigations by Mo sorbtion from technological solutions and its desorbtion from sorbents were carried out. For determination of the dynamical changing capacity (DCC) the technological solution pass through sorbtion columns with rate 5 ml/min before appearance of Mo traces that is before rushing which was determined by quantitative reaction of Mo with thiouea. After ruahing passing through of technological solutions was stopped then Mo from first column was eluated by 12,5% water solution of ammonium. 100 ml of distillated water from first column poured out from column then 100 ml of probe were selected and column with ammonium was retained for 12 h; then probe (200ml) was selected and both probes were mixed and then were analyzed/ results of investigation have shown that sorbents MDA-1 and MDA-6 have DCC sorbtion ability. For MDA-1 and MDA-6 was equaled 70,535 mg/l and 73,97 mg/l correspondently. After determination of DCC values some investigations were carried out by determination of the full dynamical changing capacity (FDCC) of sorbents. For carrying-out these investigations columns were by sorbents which were treated in above-mentioned order. Sorbtion of Mo was carried out for full rushing that is when concentration of Mo on entrance and outlite of columns was equaled. Desorbtion of Mo from sorbent was carried out accordenth to above mentioned mother. Investigation have shown that sorbents MDA-1 and MDA-6 have more high changing capacity by FDCC compression with DCC that can be explain that with increasing the sorbtion time an molibdenium ions have been sorbited by deep functional groups. This sorbtion of molibdenium from technological solutions by sorbents MDA-1 and MDA-6 have been investigaten in statical conditions. It was shown that for sorbtion of molibdenium it is enough 1,0 hour. Influence of eluent concentration on the process of desorbtion of saturated sorbents has been investigated. It was determined that at ammonium concentration more than 11,5 the full wash of molibdenium from saturated sorbents was carried out.
P-022 NEW ANION EXCHANGE SORBENT FOR INDUSTRIAL WATER TREATMENT
M.G. Mukhamediev, D.J. Bekchanov, Kh.A. Mirzakhidov
National university of Uzbekistan, polymer chemistry, Tashkent [email protected]
Synthetic ion-exchange resins are widely used in various fields: hydrometallurgy , medical, wastewater treatment , and concentration of metal ions in their analysis of solutions, based on these metallic complexes are used as catalysts [1-3]. In this work were first investigated the possibility of using an ion exchanger brand PPE- 1 based on polyvinyl chloride for industrial water treatment. The table below shows some physical and chemical characteristics of these sorbents. Table Physical-chemical properties of the sorbent in accordance with GOST 20301-74
Indicator AN-31 according to GOST
PPE- 1 , first- party PPE- 1, second - party
Appearance Yellow irregular grains
Brown irregular grains
Brown irregular grains
Granulometric composition, mm
0,5-2,0 0,4-2,0 0,4-2,0
Specific volume, cm3/g
3,3 3,6 3,6
Full of static exchange capacity, mmol/sm3
2,6 2,4 2,5
Dynamic exchange capacity , mol/m3
1280 1600 1650
Full of dynamic exchange capacity, mol/m3
- 1800 1900
For comparison, the table shows data on physical -chemical properties of the sorbent AN-31, which is used in industry for industrial water treatment. It can be seen that the proposed sorbent does not differ from the sorbent AN-31 in its physical and chemical properties. It is also seen that the dynamic exchange capacity of the sorbent PPE-1 higher than that of AN-31 sorbent. Studies allow us to recommend this exchanger for industrial water treatment. References 1. Inamuddin Dr., Mohammad Luqman // Ion Exchange Technology I Theory and Materials, -2012, -560 p. 2 . Inamuddin Dr., Mohammad Luqman // Ion Exchange Technology II Applications, -2012, -438 p.3 . 3.. Ivanov V.A., Gorshkov V.I. Sorption and chromatographic processes . -2006 . - V.6 . - Vol.1 . - P.5- 31.
P-023 HYDRODYNAMIC AND CONFORMATIONAL PARAMETERS OF LOW CHARGED COPOLYMER N-METHYL-N-VINYLACETAMIDE AND VINYL AMINE HYDROCHLORIDE AT DIFFERENT IONIC STRENGTH
O.A. Dommes1, O.V. Okatova1, N.N. Ulyanova1, I.I. Gavrilova1, E.F. Panarin1,2, G.M. Pavlov1,3
1 - Institute of Macromolecular Compounds RAS, St.-Petersburg, Russia 2 - Saint Petersburg State Polytechnical University, Department of Medical Physics and Bioengineering, St. Petersburg
Polytechnicheskaya str. 29, St. Petersburg 195251, Russia 3 - Saint Petersburg State University, Department of Physics, Ulyanovskaya str.1, St.-Petersburg 198504, Russia
Poly-N-vinylamides and cationic polyelectrolytes are actively used in biotechnology, also as flocculants for water treatment and dehydration of residues in paper production, and in cosmetics. Much interest in this class of polymers is also due to their capability to inhibit the formation of gas hydrates arising in extraction and processing of hydrocarbons. By partial hydrolysis of poly-N-vinylamides, it is possible to control the charge of a macromolecule, its hydrophobic–hydrophilic balance, and thus its complexing and flocculating properties. Linear poly(N-methyl-N-vinylacetamide) (PMVAA) has been investigated earlier [1]. In this work PMVA fractions were hydrolyzed with HCl to obtain statistical copolymer of N-methyl- N- vinylacetamide and N-methyl-N-vinylamine hydrochloride (MVAA–MVAH). The average composition of samples was 95:5%. It was realized that MVAA-MVAH copolymer demonstrates polyelectrolyte behavior in pure water solutions in contrast to the homopolymer. Molecular characteristics of the copolymer exhibited polyelectrolyte effects can be obtained only in conditions when these effects are suppressed. For this purpose the copolymer fractions were studied by velocity sedimentation, translational diffusion and intrinsic viscosity in 0.2 M NaCl aqueous solutions. Hydrodynamic and conformational characteristics as well as molar masse of isolated molecules were estimated. In addition, the intrinsic viscosity of the fractions was studied at the extreme ionic strengths – in water and in 6M NaCl. Using absolute molar masses Kuhn-Mark-Houwink-Sakurada relations for intrinsic viscosity, sedimentation and translational diffusion coefficients in 0.2 M NaCl solutions have been obtained. The Kuhn-Mark relations for the intrinsic viscosity in water and in 6M NaCl were also evaluated. Equilibrium rigidity of the macromolecules (persistence length) at different ionic strength of the solution has been estimated on the base of Gray-Bloomfield-Hearst theory, which takes into account both intramolecular draining and excluded volume effects of different nature. The results were compared with those obtained previously for the much more charged MVAA-MVAH copolymer containing about a half of charged monomer units [2]. [1]. Pavlov G.M., Okatova O.V., Mikhailova A.V., Ulyanova N.N., Gavrilova I.I., Panarin E.F. Conformational parameters of poly(N-methyl-N-vinylacetamide) molecules through the hydrodynamic characteristics studies. Macromolecular Bioscience, 2010. V. 10. P. 790-797. [2]. Pavlov G.M., Okatova O.V., Gavrilova I.I., Ulyanova N.N., Panarin E.F. Size and conformations of hydrophilic and hydrophobic polyelectrolytes in solutions of various ionic strengths. Polymer Science. A. 2013. V.55. No 12. P. 699-705.
P-024 SIZE OF LINEAR POLYELECTROLYTES WITH DIFFERENT CHARGE DENSITY IN SALT FREE AQUEOUS SOLUTIONS
O.V. Okatova1, N.N. Ulyanova1, I.I. Gavrilova1, E.F. Panarin1,2, G.M. Pavlov1,3
1 - Institute of Macromolecular Compounds RAS, St.-Petersburg, Russia 2 - Saint Petersburg State Polytechnical University, Department of Medical Physics and Bioengineering, St. Petersburg
Polytechnicheskaya str. 29, St. Petersburg 195251, Russia 3 - Saint Petersburg State University, Department of Physics, Ulyanovskaya str.1, St.-Petersburg 198504, Russia
The polyelectrolyte chains have substantially varying sizes in solutions with different ionic strength. In certain cases, the sizes of charged macromolecules may vary from the size typical of highly rigid chains to a minimum size similar to the size of globular proteins. A significant parameter determining the level of manifestation of polyelectrolyte properties is the average distance between the neighboring charges along the chain or the linear charge density. At low ionic strengths, large sizes of linear polyelectrolyte chains can be attributed to both short-range interactions (between charges proximate along the chain) and long-range interactions (between charges remote along the chain). The short- range interaction in linear macromolecules can be defined as the interaction between the repeating units (monomers) located next to one another at a distance of about the length of the statistical segment. The long-range interaction in linear macromolecules occurs between the repeating units located far from each other, i.e., the distance between the units along the chain is much greater than the statistical segment. In order to study the effect of the linear charge density on the polyelectrolyte size, the fractions of the statistical copolymer of N-methyl- N- vinylacetamide and N-methyl-N-vinylamine hydrochloride (MVAA–MVAH) at different degrees of acid hydrolysis of the initial MVAA homopolymer were synthesized and studied. The copolymer composition varied from 5 to 44 mol %. Molar masses were determined by velocity sedimentation and translational diffusion analysis which was carried out for polyelectrolyte solutions in 0.2 M NaCl with practical suppression of polyelectrolyte effects. The intrinsic viscosities of linear polyelectrolyte chains were determined in salt-free aqueous solutions over a broad range of linear charge densities and the statistical segment lengths or swelling factors for the chains were estimated. There are two approaches for interpreting large sizes of the linear chains of polyelectrolytes. One attributes the large size of chains to the electrostatic long-range effects, while the other considers this to be due to electrostatic short-range effects. The quantitative separation of these contributions is an unsolved problem in the physics of charged macromolecules. Using Kuhn–Mark–Houwink-Sakurada relations normalized to the mass of the unit chain length, it is possible to determine the conformational status of the copolymers in solutions of different ionic strengths. The obtained results provide the conclusion that intramolecular electrostatic long-range effects must be taken into account when every chain segment whose contour length corresponds to the length of the statistical segment of non-charged analog chain accommodates less than two charges. The data obtained previously for sodium polystyrene-4-sulfonate with maximum chain charge were used in the discussion. Comparison was made for macromolecules having roughly the same contour length.
P-025 SYNTHESIS AND PROPERTIES OF NOVEL BLUE, GREEN, RED LIGHT-EMITTING COPOLYFLUORENES
D.M. Ilgach1, G.I. Nosova1, I.A. Berezin1, R.Yu. Smyslov1, L.S. Litvinova1, R.M. Gadirov2,
E.N. Nikonova2, S.Yu. Nikonov2, E.N. Telminov2, T.N. Kopylova2, A.V. Yakimansky1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
2 - Tomsk State University,Tomsk, Russia [email protected]
The scientific and technological interest to conjugated copolyfluorenes (CPF) is caused by their possible applications in optoelectronic devices with optical and electric characteristics which may be tuned by variations in the chemical structure of these polymers. In the present work, Suzuki polycondensation method was used to synthesize new CPFs, containing luminophore and charge-transporting groups in the main and side chains of macromolecules. Nile red derivatives and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (T-BT-T) covalently bound to polymer chains were used as red luminophores. To control the properties of polymers, emitting only in the green spectral range, green luminophores 2,1,3-benzothiadiazole (BT) and 4-pyrrolidinyl-1,8-naphthalimide (NI) derivatives were introduced into CPF polymer chains along with charge-transporting fragments. In order to improve the conditions for an intermoelcular transfer of the excitation energy, carbazol (Cz) or diphenyloxadiazole groups were inserted into side chains of CPFs. The synthesized CPFs were end-capped with p-tert-butylbenzene, triphenylamine, naphthalbenzimidazole, diphenyloxadiazole, quinoxaline, or fluorene terminal groups, affecting both conductivity and emission color of the copolymers. Molecular-weight characteristics of the synthesized CPFs (МW = 20–120 kDa, МW/Мn = 2–2.3) and their luminescence in films were studied. Electroluminescent properties were studied for OLEDs with the architecture ITO/PEDOT:PSS/CPF/Ca/Al. It is found that at the contents of NI or BT luminophore groups >1 mol %, a complete transfer of the excitation energy from fluorene fragments to these luminophores is observed in photoluminescence spectra of CPF films. However, higher contents of NI and BT (> 2 mol%) are necessary to quench the blue emission of polyfluorene backbone in electroluminescence spectra. For BT-containing CPFs, the electroluminescence brightness varied from 600 to 4500 cd/m2 at the voltage 10 V, depending on the content of BT and other comonomer units, film thickness, and the method of film preparation (spin-coating or ink-jet printing), and the emission color was close to green. CPFs with red electroluminescence (CIE coordinates: x=0,644 y=0,327) were obtained with the use of T-BT-T comonomer luminophore units. A stable blue electroluminescence (CIE coordinates: x=0,21 y=0,21) was attained for poly[9,9-bis(4-(hexyloxy)phenyl)-9H-fluorene]. Poly[9,9-dioctyl-9H-fluorene] has a rather weak blue electroluminescence. However, the introduction of 1 mol % 3,6-di-Br-carbazole comonomer units with NI fragments in side chains resulted in a sharp increase in the electroluminescence brightness up to 1400 cd/m2 (at 10 V). The work is supported by the Scientific Program of the Presidium of the Russian Academy of Sciences “Multifunctional materials for molecular electronics” (coordinator – academician S.M. Aldoshin) and grant «UMNIK» № 0002711.
P-026 EFFECT OF THE INTERNAL RIGIDITY AND BRANCHING ANISOTROPY ON THE STRUCTURAL CHARACTERISTICS OF
DENDRIMERS
I.V. Michailov1, О.V. Shavykin2, А.А. Darinskii1 1 - Institute of Macromolecular Compound of Russian Academy of Sciences, Saint-Petersburg, Russia
2 - Tver State University, Tver, Russia [email protected]
Dendrimers are regular branched macromolecules with the well-defined architecture. In spite of the rather long history they attract till now an interest due to their possible applications in the nanotechnology and nanomedicine. Computer simulation is the most powerful method of their theoretical investigation. In contrast to full-atomic models the use of coarse-grained models allows to predict universal properties of the definite class of dendrimers. There are many simulations of dendrimers but the majority of them use the models with the symmetric branching and with flexible repeating units. However there is a substantial rigidity both of spacers and branching angles in many real dendrimers.There is also a class of dendrimers with the asymmetric branching, such as poly-L-lysine dendrimers, for example. We have performed the Langevene dynamics simulation to reveal an effect of the branching asymmetry and internal rigidity on the structural characteristics of dendrimers. Macromolecules with the same generation number and the average length of spacers but differing in the branching asymmetry and internal rigidity were considered. Our data show that both the branching anisotropy and rigidity of units have a weak influence on the size and shape, as well as on the internal density profile. On the other hand, the branching anisotropy and the unit’s rigidity lead to the difference in the deformation and orientation of spacers as compared to their symmetric and flexible analogs. This work was supported by RFBR grant 13-03-00524
P-027 THERMAL BEHAVIOR OF NARROW DISPERSED ACRYLONITRILE COPOLYMERS SYNTHESIZED VIA RAFT
TECHNIQUE
J.V. Kostina1, E.V. Chernikova2, A.A. Baskakov1, S.M. Kishilov2, A.V. Plutalova3, A.Yu. Nikolaev3
1 - A.V. Topchiev Institute of Petrochemical Synthesis of RAS, Moscow, Russia 2 - Polymer Chair, Faculty of Chemistry, Lomonosov Moscow State University, Moscow, Russia
3 - Moscow University of Fine Chemical Technology, Moscow, Russia [email protected]
Polyconjugated system (PCS) formation under thermal treatment of PAN is one of the most studied intramolecular thermochemical reaction. The incorporation of low amount of monomer units of another chemical nature into macromolecule of PAN may change the thermal behavior of reaction drastically due to breaking of chain structure regularity. Beside, the comonomer may induce cyclization reaction as well as thermal destruction of polymer. However, there is still no correlation found between copolymer composition, chain microstructure, molecular mass distribution, chain branching, etc. and thermal behavior of copolymer during low-temperature pyrolysis; the reason may come from simultaneous variation of several parameters during copolymer synthesis. To solve this problem the controlled radical polymerization may be used. Recently we have developed the technique of controlled synthesis of narrow dispersed (Mw/Mn = 1.3 – 1.4) acrylonitrile copolymers with low content of the second monomer based on RAFT polymerization in the presence of symmetrical trithiocarbonates. In this research we present the results of the investigation of thermal behavior of the synthesized copolymers, in which the nature (styrene; methyl, n- and tert-butyl acrylate, acrylamide) and the content of the second monomer (2 – 10 mol. %) were varied. All the copolymers were obtained in DMSO at 80oC at limited conversions and were characterized by Mn about 30 – 35 kDa and Mw/Mn=1.3 – 1.4. According to DSC study the studied copolymers may be divided in two groups. The first group comprises copolymers of styrene, methyl and n-butyl acrylate. The higher is the content of second comonomer the higher is the temperature of thermal cyclization and the lower is the value of exo-effect on the DSC-curves. Copolymers containing tert-butyl acrylate and acrylamide can be referred to the second group. In this case thermal cyclization starts at lower temperature comparing to homopolymer; the higher is the amount of the second monomer the more pronounced is this effect. PCS structure formation was studied by means of IR-pyrolysis. As a result the copolymers also can be divided in two groups. All alkyl acrylate copolymers form more short chains PCS comparing to PAN, but in general its structure remains the same. In contrast, the incorporation of styrene or acrylamide leads to formation of PCS of another structure. The results obtained are discussed. This work was supported by Russian Foundation for Basic Researches (project No 14-03-00155 and 14-03-00142).
P-028 STRUCTURAL ORGANIZATION OF LANGMUIR- BLODGETT COMBLIKE POLYAMIC ACID SALT IN MIXED SOLVENTS
V.P. Sklizkova1, N.D. Stepina2, V.V. Kudryavtsev1, V.M. Svetlichnyi1, R.V. Gainutdinov2,
A.L. Tolstikhina2 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St.Petersburg
2 - Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow [email protected]
Langmuir-Blodgett (LB) films of comblike polyamic acid salt (PAAS) from mixed solvents DMAA/benzene, N-methyl-2-pyrrolidone/benzol, and DMAA/dioxane at a ratio close to polymer precipitation were obtained. PAAS synthesized on the basis of 3,3',4,4'- biphenyltetracarboxylic dianhydride and o-tolidine (PAAS) with monochain tert-amine N,N-dimethylhexadecylamine. A comparative analysis of the influence of the solvent nature on the LB films morphology was carried out by scanning atomic-force microscope (AFM). Nanofilms were formed by transferring Langmuir monolayers onto a solid substrate at surface pressures 3 mN/m , 25 mN/m , 35 mN/m by vertical (LB) and horizontal (LS) methods. The images of the surface with scanning areas 9000х9000nm, 1300х1300nm, 450х450nm were used to obtain more accurate information about the nanofilms structure. The peculiarities of structure types of surface microrelief, sizes and shapes of formations, and surface roughness were investigated. The results of statistical processing of AFM data showed that histograms of the particle size distribution in films prepared using the vertical and horizontal lift were markedly different. It was observed mostly unimodal particle size distribution. It was shown that the nature of the PAAS solvent affects the structure of LB film that is reflected in the change in the form of compression isotherms of Langmuir monolayers and surface topography of the film. LB films obtained from a solution of the salt in a mixed solvent of DMAA/benzene have higher smoothness and uniformity than from N-methyl-2-pyrrolidone/benzol, and DMAA/dioxane solutions. Analysis of surface roughness of LB films by Spip, Image metrology program showed that the degree of aggregation, orientation and uniformity of the film structural elements depends on the nature of the solvent and conditions of films formation.
P-029 STAR BRUSHES SUBJECTED TO DEFORMATION: STRUCTURE AND THERMODYNAMICS
A.K. Misorin1, A.A. Polotsky2, T.M. Birshtein1
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia and St. Petersburg State University, Physics Department, St. Petersburg, Russia
2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia and St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia
Layers of polymers densely grafted to impenetrable surfaces, or polymer brushes, are intensively studied, both experimentally and theoretically, for more than 30 years, and the interest to such systems is keeping on growing. Practical interest to polymer brushes is motivated by its use in surface modification. The present work is devoted to theoretical study of brushes made of arm-grafted polymer stars. Earlier self-consistent field (SCF) modeling [1, 2] and Langevin dynamics simulation [3] studies have revealed a non-trivial structure of the star brush at moderate grafting density: At moderate and high grafting density the stars in the brush are divided into two populations (i) those with weakly extended arms and (ii) those with a very strongly stretched grafting arm (stem) and all free arms extended toward the solvent. We propose a simple mean-field theory of the star brush that takes into account its two-population structure. The theory is based on a box-like model of the brush: The brush is divided into two parts, in the inner part, close to the grafting surface, stars of weakly stretched population and stems of extended stars are found while the free arms of extended stars are located in the outer part of the brush. The polymer density profile in the brush is assumed to have a “two-step” shape. Stars in the extended population are assumed to be equally stretched, the position of extended stars’ branching points sets the boundary between two parts of the brush. This model is very similar to that introduced by Merlitz et al. [4], except that in [4] polymer density in two parts of the brush was the same (and the profile was a “one-step”). We show that the theory quantatively accurately describes earlier numerical SCF results [2] for free star brush. We study compression of a star brush by an impenetrable plane by using the Scheuejens-Fleer numerical SCF approach and by applying the developed mean-field theory. Again, a very good quantitative agreement is observed. In particular, it is demonstrated than deformation affects the two-population structure of the star brush; moreover, the effect essentially depends on the density at which stars are grafted: in sparsely grafted brushes the fraction of stars in the stretched population increases while in densely grafted brushes it decreases with deformation. Acknowledgements. This work is supported by the Russian Foundation for Basic Research (grant 14-03-00372-а), by the Department of Chemistry and Material Science of the Russian Academy of Sciences, and by the Government of Russian Federation (grant 074-U01). [1] A. A. Polotsky, T. Gillich, O. V. Borisov, F. A. M. Leermakers, M. Textor and T. M. Birshtein, Macromolecules, 2010, 43, 9555. [2] A. A. Polotsky, F. A. M. Leermakers, E. B. Zhulina and T. M. Birshtein, Macromolecules, 2012, 45, 7260. [3] H. Merlitz, C.-X. Wu and J.-U. Sommer, Macromolecules, 2011, 44, 7043–7049. [4] H. Merlitz, W. Cui, C.-X. Wu and J.-U. Sommer, Macromolecules, 2013, 46, 1248–1252.
P-030 CHROMATOGRAPHIC ANALYSIS OF STRUCTURAL ELEMENTS OF MACROMOLECULAR POLYIMIDE BRUSHES WITH
POLYMETHACRYLATE SIDE CHAINS
L.S. Litvinova, I.P. Lezin, D.M. Ilgach, T.K. Meleshko, N.N. Bogorad, N.V. Kukarkina, L.V. Vinogradova, A.V. Yakimansky
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, 199004, Saint-Petersburg, Russia
The critical mode of chromatography of macromolecules is a specific separation regime on the boundary between exclusion and adsorption regimes that is based on the system properties in the vicinity of the critical adsorption point. Under this mode, macromolecules are no more separated according to their sizes, and this makes it possible to study various types of their structural and topological heterogeneities as well as to determine the distribution of different types of functional groups in macromolecules. We used adsorption chromatography at the critical conditions (ACCC) for the analysis of polymethylmethacrylate (PMMA) and poly(tert-butylmethacrylate) (PTBMA) side chains cleaved from polyimide (PI) regular PI-graft-PMMA and PI-graft-PTBMA molecular brushes synthesized via atom transfer radical polymerization (ATRP) of methacrylates by polyimide multicenter macroinitiators. PMMA and PTBMA side chains were cleaved by means of alkaline hydrolysis of the PI backbone, and, therefore, they had to contain one terminal COOH group, and might also have one OH group at the opposite chain end. It could not be excluded beforehand that cleaved chains also contain a certain amount of non-terminal methacrylic acid units if the alkaline hydrolysis of the PI backbone would be accompanied by a partial hydrolysis of ester groups of PMMA and PTBMA side chains. Therefore, a careful analysis of molecular-weight characteristics of side chains and distributions of functional groups in side chains was necessary in order to verify a controlled character of the ATRP process of the synthesis of polyimide brushes and to prove that middle units of cleaved side chains remain intact under the alkaline hydrolysis of the PI backbone. To this aim, mobile phases were composed in which either adsorption or exclusion regimes or ACCC are realized for 1) commercial PMMA and PTBMA homopolymers, containing neither COOH nor OH terminal functional groups, and 2) PMMA and PTBMA cleaved side chains with one or more polar terminal groups and possibly some middle COOH groups. It was shown that both PMMA and PTBMA cleaved side chains are functionally polydisperse (contain different sets of end functional groups), however, there are no carboxylic groups in their middle units. Temperature dependences of retention factors at the critical conditions are determined for the studied PMMA and PTBMA polymers and their thermodynamic sorption characteristics are determined. The work is supported by the Russian Foundation for Basic Research (grant 14-03-31809-mol-a).
P-031 SYNTHESIS OF POLYIMIDE BRUSHES WITH AMPHIPHILIC BLOCK-COPOLYMER SIDE CHAINS
A.V. Kashina, T.K. Meleshko, L.S. Litvinova, I.V. Ivanov, N.V. Kukarkina, A.V. Yakimansky
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004 Russia [email protected]
Owing to their specific properties, amphiphilic polymers have wide possibilities of applications for solubilization, targeted drug delivery, catalysis, coating modification, synthesis of engineered nanoparticles. Amphiphilic graft-copolymers of regular structure with narrow dispersed densely grafted side chains (polymer brushes) is of particular interest. Amphiphilic graft-copolymers with a hydrophobic polyimide (PI) main chain and hydrophilic polymethacrylic acid (PMAA) side chains (PI-graft-PMAA) as well as amphiphilic block-copolymer side chains, involving PMAA and polymethylmethacrylate (PMMA) blocks (PI-graft-(PMAA-block-PMMA), were synthesized by atom transfer radical polymerization (ATRP) method.
O O
N
O
O O
C
N
O
OO
CH3H3C
CH2
CH3CO
OH
CH2
CH3CO
OCH3
Br
O O
N
O
O O
C
N
O
OO
CH3H3C
CH2
CH3CO
OH
Br
n
p
n
p
k
PI-graft-PMAA PI-graft-(PMAA-block-PMMA)
Polyimide brushes PI-graft-(PMAA-block-PMMA) were obtained from PI-graft-(PtBMA-block-PMMA) precursors via acidic hydrolysis of the poly(tert-butylmethacrylate) (PtBMA) block. The synthesis of PI-graft-(PtBMA-block-PMMA) polyimide brushes was performed under different conditions, allowing the grafting density of block-copolymer side chains as well as the lengths of the first and second blocks to be varied. The obtained graft-copolyimides and their cleaved side chains were characterized by IR, 1H NMR spectroscopy, and GPC methods. For the cleavage of side chains, PI-graft-PtBMA and PI-graft-(PtBMA-block-PMMA) polyimide brushes were subjected to an alkaline hydrolysis of the polyimide backbone under carefully optimized conditions, avoiding a saponification of ester groups of thus separated side chains. The experimental molecular weights values for cleaved side chains determined by the GPC method were compared to theoretical molecular weight values found from the monomer conversion. Such a comparison allowed us to estimate the ATRP initiation efficiency, characterizing the grafting density of side chains. It was shown that the grafting density is ~1 side chain per 2-3 monomer units of the PI backbone, depending on the synthetic conditions.
P-032 SYNTHESIS OF POLYMER BRUSHES USING DIRECT ATRP AND AGET ATRP OF METHACRYLATES BY A MULTICENTER POLYIMIDE
MACROINITIATOR
I.V. Ivanov, T.K. Meleshko, L.S. Litvinova, A.V. Kashina, D.M. Ilgach, N.N. Bogorad, A.V. Yakimansky
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, St.Petersburg, 199004 Russia [email protected]
In the past decade, an extensive development of controlled radical polymerization (CRP) methods resulted in the synthesis of numerous well-defined copolymers with complex architectures. Among these systems, regular graft-copolymers with narrow dispersed side chains (polymer brushes) are worth of emphasizing. Specifying the chemical structure, the main and side chains dimensions as well as the grafting density, it is possible to vary characteristics of macromolecules in a wide range. This opens up new opportunities for the creation of new materials with advanced properties. Graft-copolymers derived from blocks, differing in their chemical nature and thermodynamic properties, are of special interest. In particular, our research is focused on polymer brushes with a polyimide (PI) main chain and polymethylmethacrylate (PMMA) or poly tert-butyl methacrylate (PtBMA) side chains. An important task is to develop an optimal method for the synthesis of graft-copolymers, allowing one to adjust the grafting density of side chains, their length and dispersity in a controlled fashion. Atom transfer radical polymerization (ATRP) is one of the most successful CRP methods for the synthesis of polymers with predictable molecular weights (MW) and well-defined architectures. However, direct ATRP methods have some limitations such as a high sensitivity of the catalyst used to traces of oxygen in the reaction mixture. An alternative “activators generated by electron transfer” (AGET) ATRP approach was recently developed to overcome this drawback. That technique employs oxidized catalyst complexes that are activated in the presence of various reducing agents. In the present work, graft-copolymers PI-graft-PMMA and PI-graft-PtBMA
R = -CH3, -C(CH3)3
were synthesized, using multicenter polyimide macroinitiator by both ATRP and AGET ATRP methods, and their results were compared. It was shown that first-order kinetic plots as well as dependences of MW of cleaved side chains on the monomer conversion are linear, indicating the absence of irreversible chain termination and chain transfer reactions, respectively. These results together with a rather narrow molecular weight distribution of cleaved PMMA or PtBMA side chains indicate a well-controlled character of the processes studied under the determined optimal conditions. Strong interactions between hydrophobic PMMA side chains, characteristic of polymer brushes, makes it possible to use PI-graft-PMMA for the formation of nanoscale multilayer Langmuir-Blodgett films, which are used in various high-technology applications. Langmuir monolayers were formed on the surface of water from chloroform solutions of PI-graft-PMMA, the dependence of the parameters of these monolayers on the length of PMMA side chains were studied.
P-033 SYNTHESIS OF THERMO- AND PH-RESPONSIVE POLYIMIDE BRUSHES WITH POLY[2-(N,N–DIMETHYLAMINO) ETHYL
METHACRYLATE] SIDE CHAINS
A.S. Sasina, I.V. Ivanov, D.M. Ilgach, T.K. Meleshko, L.S. Litvinova, A.V. Yakimansky Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, St.Petersburg, 199004 Russia
Among the so-called "smart" polymers, copolymers of complex architecture with poly-N,N-dimethylaminoethyl methacrylate (PDMAEMA) backbone or side chains have attracted much attention. These polymers are water-soluble, pH- and thermo-responsive, and their polycations formed due to the protonation of PDMAEMA amino groups in aqueous media are able to form interpolyelectrolyte complexes with widely variable properties. In the past few years, an enormous progress was achieved in the development of methods of the synthesis and studies of regular graft-copolymers with narrow dispersed densely grafted side chains (polymer brushes). It was of interest to develop a method for the synthesis of regular graft-copolymers, containing a polyimide (PI) main chain and covalently attached PDMAEMA side chains. Such polyelectrolyte polymer brushes are promising for using in many nanotechnology applications, e.g., as templates and nanocontainers for metal nanoparticles, materials for efficient diffusion membranes, etc. New water-soluble polyimide brushes with PDMAEMA side chains of different lengths were synthesized by the method of atom transfer radical polymerization (ATRP) from a multi-center polyimide macroinitiator.
O O
N N
O
O
O
O O
C O
CH3H3C
CH2
n
CH3CO
O
q
NCH3
CH3
The quaternization of PI-graft-PDMAEMA brushes by methyl iodide followed by alkaline hydrolysis of quaternized copolymers, leading to a degradation of the polyimide backbone and polymer-analogous transformations of cleaved PDMAEMA side chains to polymethacrylic acid, was carried out. Resulting copolyimides and cleaved side chain of polymethacrylic acid were characterized by IR, NMR, UV spectroscopy and GPC. A possibility to produce silver nanoparticles stabilized by water-soluble PI-graft-PDMAEMA brushes was approved.
P-034 THE STUDY OF POLY-3-HEXYLTHIOPHENE CONFORMATION IN SOLUTION
A.V. Yakimansky1, S.V. Bushin1, M.A. Bezrukova1, A.A. Lezov2, L.I. Аkhmadeeva2,
E.V. Lebedeva2, A.S. Gubarev2, N.V. Tsvetkov2, G. Koeckelberghs3, T. Verbiest3, A. Persoons3 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, 199004 St. Petersburg,
Russia 2 - Saint-Petersburg State University, Department of Physics, Ulianovskaya ul. 3, Petrodvoretz, St.Petersburg, 198504
Russia 3 - Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Belgium
Molecular hydrodynamics methods, dynamic and static light scattering (DLS, SLS) were used in the studies of 11 poly-3-hexylthiophene samples (solutions in chloroform). In relaxation time spectra of all samples, sets of peaks are present; the shortest relaxation times corresponded to translational diffusion of individual macromolecules. Quantitative assessment of individual molecules content showed that more than 95% of these particles are present in the studied samples. However, the presence of 5% of large particles led to considerable distortion in statistical light scattering data. The calculations of molecular masses of polymers were performed using sedimentation analysis data combined with dynamic scattering and diffusion analysis data. A Mettler Toledo DM-40 instrument was used in determination of partial specific volume of samples. The range of molecular masses MsD was 2300-15200. The dependences of intrinsic viscosity [], translational diffusion coefficients D and sedimentation coefficients s on MsD were established: [] = 6.9410-5MsD
0.880.04 ; D = 3.9010-4MsD-0.600.01 ; s = 4.1110-15MsD
0.400.01. High exponents in the Mark-Kuhn-Houwink equations for [] and D at MsD values not exceeding 15000 should be considered as a manifestation of percolation during translational and rotational motions of macromolecules. Hydrodynamic properties of molecules were interpreted using the HWC model (Hiromi Yamakawa, 1977). The polymer demonstrated the following molecular and conformational parameters: persistence length a = 34 Å, hydrodynamic diameter of macromolecule d ≈ 10 Å, mass of a unit of length along the persistence direction ML = 53.5 Å–1. The ML is 30% higher than the M0/ relationship (where M0 and are the mass and the length of monomer unit, respectively), this fact indicating that poly-3-hexylthiophene is coiled inside the Kuhn segment.
P-035 THE COMPARISON BETWEEN HYDRODYNAMICAL AND CONFORMATIONAL PROPERTIES OF CELLULOSE TRIDECANOATE
AND CELLULOSE ACETOMYRISTINATE IN SOLUTIONS
E.P. Astapenko, M.A. Bezrukova, S.V. Bushin, A.K. Khripunov Institute of Macromolecular Compounds RAS, Bolshoy pr. 31, St. Petersburg, 199004 Russia
The molecular characteristics of cellulose tridecanoate, CTD (degree of substitution, DS = 165÷240) studied previously [1] correspond to the worm-like chain model with the following parameters: the Kunh length А = 290 Ǻ, the hydrodynamical diameter of chain dhydr = 19 Ǻ (which is virtually similar to the diameter dv = 15 Ǻ calculated from polymer density value). The directions of CTD chain and statistical segment are similar. The shift of DS range of CTD from DS = 165÷240 to the region of higher degrees of substitution (DS = 230÷290) in going to cellulose acetomyristinate (CAM) with close lengths of side aliphatic chains in both polymers is related to appearance of secondary structure. This phenomenon manifests itself in increase (practically by a factor of two [2]) of monomer unit density along the statistical segment direction. This conclusion was confirmed by measurements of temperature [2]. The temperature coefficients of rigidity (S) for CTD and CAM remain negative, which is characteristic of rigid chain polymers. At the same time, the potential of hindrance of the internal rotations U0 in the case of CTD decreases with increasing temperature T (dU0/dT < 0), and in the case of CAM, the U0 potential increases with increasing temperature (dU0/dT > 0). The effect of temperature stabilization of CAM conformation can be attributed to increase (in going from CTD to CAM) in the density of aliphatic phase surrounding macromolecule and stronger interactions between aliphatic side substituents which unfold with increasing temperature in high-density aliphatic phase (the case of CAM with high DS). However, in aliphatic phase with lower density (the case of CTD with low DS) this effect was not observed. The singularity and novelty of the observed effects require confirmation by thorough studies of the same polymer. In our work, CTD samples with sufficiently low molecular masses were obtained. Thus, it is possible to use direct hydrodynamic method to determine molecular mass of unit length along the statistical segment (the “shift factor” ML value), statistical segment length A and asymmetry A/d (relative diameter d/A) of the statistical segment. [1] S. V. Bushin, N. V. Tsvetkov, M. A. Bezrukova, E. P. Astapenko, E. V. Lebedeva, A. N. Podseval’nikova, V. O. Ivanova, A. V. Pavlov, A. K. Khripunov. Russian Journal of Applied Chemistry. 2012, V. 85, No. 6, PP. 963-968. [2] S. V. Bushin, A. K. Khripunov, M. A. Bezrukova, E. P. Astapenko. Polymer Science Ser. A. 2007. V. 49, No. 1, P. 71-76.
P-036 INVESTIGATION OF SIC NANOLAYERS FORMED BY THERMAL CARBONIZATION OF RIGID-CHAIN POLYIMIDE LANGMUIR-
BLODGETT FILMS ON SILICON
S.I. Goloudina1, V.V. Luchinin1, V.M. Pasyuta1, M.F. Panov1, V.V. Klechkovskaya2, T.F. Semenova3, V.P. Sklizkova4, I.V. Gofman4, V.M. Svetlychnyi4, V.V. Kudryavtsev4
1 - Saint Petersburg State Electrotechnical University, St.Petersburg, Russia 2 - Shubnicov Institute of Crystallography, RAS, Moscow, Russia
3 - Saint Petersburg State University, St. Petersburg, Russia 4 - Institute of Macromolecular Compounds, RAS, St. Petersburg, Russia
Silicon carbide (SiC) is a wide band-gap semiconductor, possessing a unique combination of properties for device application. Recently the fabrication of SiC thin films on silicon (Si) has attracted increasing interest. SiC nanometer flms can be obtained by carbonization of polyimide Langmuir-Blodgett (LB) films on Si substrate. The aim of our work was to prepare and study of SiC layers formed by carbonization of rigid-chain polyimide (BPDA-oTD). As polyimide prepolymer we used comb-like rigid-chain polyamic acid alkylammonium salt with tertiary amine multichains (PAAS) synthesized on the basis of 3,3',4,4'-diphenyltetracarboxylic acid dianhydride and o-tolidine with tert-amine o,o',o''-trihexadecanoyltriethanolamine. PAAS LB films of 21, 81 and 121 layers were deposited on Si (100) and (111). The polyimide films were formed by therminal imidization of PAAS LB films. The thickness of PI films measured by ellipsometry method were 10, 47, 54 nm, respectively. Carbonization of the polyimide films was carried out in vacuum (1×10-5mbar) at 1000˚C for 1 hour. Formation of -SiC films were confirmed by Fourier transform infrared technique, Reflection High-Energy Electron Diffraction and X-ray difraction. It was shown the degree of crystallinity of the -SiC layers on Si (111) was greater than on Si (100). AFM images of SiC films showed that the surface structure of SiC films inherits the domain structure of the PI films.
P-037 PROPERTIES OF GRAFTED COPOLYMER WITH POLYIMIDE BACKBONE AND POLY-TERT-BUTYLMETHACRYLATE SIDE CHAINS
IN SOLUTIONS
N.V. Zakharova, A.P. Filippov, E.B. Tarabukina, E.V. Belyaeva, T.K. Meleshko, D.M. Ilgach, N.N. Bogorad, A.V. Yakimansky
Institute of Macromolecular Compounds of Russian Academy of Sciences, Saint-Petersburg, Russia [email protected]
In order to find out the connection between the molecular structure and the solution properties of polymers with complex architecture the polymer brushes with polyimide main chain and poly-tert-butylmethacrylate side chains were studied by the methods of molecular optics and hydrodynamics (velocity sedimentation, translational diffusion, viscometry, and light scattering). The investigated polymer brushes have following structure:
N
O
O O
O
N
O O
n1N
O
O O
O
N
O O
OH
n2
O
CO
CCH3 CH3
[CH2-C(CH)3]m
CO
OC(CH3)3 The samples under investigation differed by density z = n1/(n1 + n2) of side-chain grafting to the backbone (z = 0.5 1) and polymerization degree P of side chains (P = 50 150). The experiments are carried out in the chloroform and toluene which are the good solvents for copolymers and side chains. The polyimide does not dissolve in toluene, chloroform is poor solvent for backbone. The values of the molar masses, the second virial coefficient A2, the intrinsic viscosity [η], the radius of gyration Rg, and the hydrodynamic radius Rh of macromolecules were determined. Taking into account the thermodynamical quality of the solvents, it may be assumed that the polyimide backbone tends to be hidden from the solvents inside molecular coils of side chains. The molecular-weight dependences of [η], Rg, and Rh have been analyzed using the wormlike spherocylinder model. It was shown that Kuhn segment length A and hydrodynamic diameter d of spherocylinder increase with side chain lengthening. This work was supported by Program No 3 of Department of Chemistry and Material Sciences of Russian Academy of Sciences.
P-038 PROPERTIES OF POLYPEPTIDE PLANE BRUSHES
E.N. Vlasova, B.Z. Volchek Institute of macromolecular compounds RAS, St.-Petersburg, Russia
Polymeric brushes consisting of poly-(-L-benzyl glutamate) (PLBG) chains connected by their carboxylic ends to silicon plates were prepared by Surface-Initiated Vapor Deposition Polymerization (SIVDP) of N-carboxy anhydride of -benzyl-glutamate (NCA--BG) on the amino groups of aminoalkyl-silanes of the silicon substrates (triethoxysilane, APES) or (-aminopropyl or trimethoxysilane, APMS)1. PLGA silicon brushes were prepared by treatment of PBLG brushes with mixture of trifluoroacetic acid and trifluorosulfonic acid. FTIR spectroscopy was used for determination of conformational and orientational characteristics and also molecular masses of polymer chains grafted to the surface.
1800 1700 1600 1500 14000,00
0,01
0,02
0,03
0,04
0,05
0,06
0,07
0,08
0,09
0,10
1550
1650
2
1
Wavenumber cm-1
IR absorption spectra of PLBG brushes (1), placed in chloroform (2)
1800 1700 1600 1500 1400
0,00
0,01
0,02
0,03
0,04
0,05
0,06
0,07 1651
1549
2
1
Wavenumber cm-1
IR absorption spectra of PLGA (1), placed in D2O (2)
Orientation parameters of polypeptide moiety of the polymer brushes were determined2. It was found that in good solvents for PBLGA moiety (chlorophorm) and for PGA moiety (H2O and D2O) homotropic orientation of polypeptide to silicon plates take place with parameter of order S 1, which was determined according to formula S=0.5(3cos2 - 1). Oriented polymeric brushes can be used as good dividing systems for different organic compounds. Separating properties depend on free volume and determined by density of macromolecules on the surface. Penetrability of substances with different structures and molecular weight (polystyrene, polyethylenglycol of different M.M. aliphatic alcohols and acids for PLBG; polyethylenglycol, proteins of different M.M.) into oriented brushes was examined. High density of bonding of rigid polypeptide chains to surfaces results in stabilization of – helix conformation3. Therefore perhaps conformational composition during – helix –coil transition of macromolecules in brushes differs from those in free macromolecules. Change of form of coil may occur by two ways: increasing of amount of elongated conformers like - structure, or redistribution of conformers of chain. According spectral characteristics of Amide I band in IR spectra of polypeptide brushes, extension of macromolecules homeotropic to plane does not accompanied by formation of long - structure consecutions and occurs by second way. References
[1] Y. Wang,Y-C Chang // Langmur 2002, 18, 9859 [2] E. Vlasova, B. Volchek, I. Tarasenko, G. Vlasov Macromolecular Symposia, 2011 v.305, p.116-121 [3] Y. Wang, Y-C Chang // Macromolecules 2003, 36, 65003-6510
P-039 INFLUENCE OF THE THERMODYNAMIC QUALITY OF THE SOLVENT ON THE HYDRODYNAMIC AND CONFORMATIONAL PROPERTIES OF THE POLYIMIDE/POLYSTYRENE GRAFTED
COPOLYMERS
E.V. Belyaeva, A.P. Filippov, T.K. Meleshko, D.M. Ilgach, N.N. Bogorad, A.V. Yakimansky Institute of Macromolecular Compounds of Russian Academy of Sciences, Saint-Petersburg, Russia
The aim of the present work is to study the influence of the thermodynamic quality of the solvent on the hydrodynamic and conformational properties of grafted copolymer PI-g-PS with polyimide (PI) main chain and polystyrene (PS) side chains:
CH3
N
O
O O
O
N
O O
n1
O
CO
CCH3
[CH2-CH]m
N
O
O O
O
N
O O
OH
n2
The density of side-chain grafting to the backbone is close to 1 (n1 >> n2) and the polymerization degree of PS chains P is equal to 25. The copolymer was investigated using static and dynamic light scattering and capillary viscometry methods in solutions in chloroform, toluene, and mixed solvent (cyclohexane (99% w.) and chloroform (1% w.)). The chloroform and toluene are the good solvents for PI-g-PS. The mixed solvent is -solvent at 27C. The temperature dependences of the intrinsic viscosity [η], the hydrodynamic radius Rh, and the radius of gyration Rg of macromolecules were determined. The analysis of obtained experimental results makes it possible to assume that the hydrodynamic behavior of the PI-g-PS molecules in the good solvents may be described adequately using the wormlike spherocylinder model. We estimated parameters of the model spherocylinder: Kuhn segment length A 22 nm and hydrodynamic diameter d 15 nm. In ideal solvent the PI-g-PS molecules may be modeled by the rigid prolate rotational ellipsoid with semimajor La and semiminor Lb axes. In the -conditions, the p = La/Lb ratio is close to 1.3. The p value increases slightly with temperature growth and achieves p = 1.5 at the temperature T = + 25C. This work was supported by Program No 3 of Department of Chemistry and Material Sciences of Russian Academy of Sciences.
P-040 POLYMERS WITH IONIC BOND SIDE CHAINS: MOLECULAR, CONFORMATIONAL AND OPTICAL PROPERTIES IN ORGANIC
SOLVENTS
N.G. Mikusheva1, L.I. Akhmadeeva1, A.N. Podsevalnikova1, E.V. Lebedeva1, A.A. Lezov1, A.S. Gubarev1, M.E. Mikhailova1, I.P. Kolomiets1, N.V. Tsvetkov1, L.N. Andreeva2,
M.A. Bezrukova2, S.V. Bushin2, I.M. Zorin3, T.M. Shcherbinina3, A.Yu. Bilibin3 1 - Faculty of Physics, St. Petersburg State University, Ul’yanovskaya ul. 1, Saint Petersburg, 198504, Russia
2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31 (V.O.), St. Petersburg, 199034, Russia
3 - Institute of Chemistry, St. Petersburg State University, Universitetskii pr. 26, St. Petersburg, 198504, Russia [email protected]
Creation and research of complex structured polymer systems is an actual direction in the development of polymer science. This structures are widely applied at the creation and design of biological systems based on them. Very interesting objects in this field are polymers obtained by the polymerization of ionic surfactants in micellar state [1, 2]. The structure of these products depends on the structure of monomers, mainly on the position of a polymerizable bond in them, on the concentration of monomers in the solution to the synthesis begins, and on used solvent [2, 3]. Such polymers, for example, are ionic bond side chains polymers: poly(cetylammonium 2-acrylamino-2-methylpropanesulfonate) (CA-PAMPS) and poly(dodecylammonium 2-acrylamido-2-methylpropanesulfonate) (DDA-PAMPS), obtained under different conditions of synthesis. The present work concerns the study of a number of these samples with various molecular masses in dilute solutions in different organic solvents (chloroform and dimethyl sulfoxide containing small amounts of LiCl) by the methods of viscometry, dynamic light scattering, isothermal diffusion, sedimentation, flow birefringence and equilibrium and non- equilibrium electric birefringence. Conformational characteristics were defined: the Kuhn segment length A (CA-PAMPS) = 4.5 nm, A (DDA-PAMPS) = 5 nm, the polymer chain diameter d (CA-PAMPS) = 1.8 nm, d (DDA-PAMPS) = 1.6 nm [2]. The Mark-Kuhn-Houwink equations were received; the inherent optical anisotropy of the segment was defined. The equilibrium and non- equilibrium electric birefringence properties were studied. On the basis of the received data optical and conformational properties of polymer CA-PAMPS and DDA-PAMPS were compared. The influence of the synthesis conditions and the length of the side chains was studied. 1. N.V. Tsvetkov, L.N. Andreeva, I.M. Zorin, S.V. Bushin, E.V. Lebedeva, I.A. Strelina, M.A. Bezrukova, A.A. Lezov, I.A. Makarov, and A.Yu. Bilibin, Polymer Science, Ser. A 53, 355 (2011). 2. L.N. Andreeva, T.M. Shcherbinina, I.M. Zorin, M.A. Bezrukova, S.V. Bushin, and A.Yu. Bilibin, Polymer Science, Ser. A 55, 289 (2013). 3. A.Yu. Bilibin, T.M. Sukhanova, N.I. Matuschkin, A.B. Mel’nikov, I.M. Zorin, Macromol. Symp. 317-318, 160 (2012) This work was supported by the Russian Foundation for Basic Research (12-03-00687-а, 13-03-00474) and St. Petersburg State University (scientific research 11.38.267.2014).
P-041 SURFACE MODIFICATION OF ELECTROSPUN POLY (ACRYLONITRILE-CO- STYRENE) COPOLYMER NANOFIBERS
TOWARDS DEVELOPING A DYE REMOVAL
M.R. El-Aassar1, M.F. El-Kady2, H. Sh. Hassan3 1 - Polymer Materials Research Department, Institute of Advanced Technology and New Material, City of Scientific
Research and Technology Applications, New Borg El-Arab City 21934, Alexandria, Egypt 2 - Chemical and Petrochemicals Engineering Department, Engineering Faculty, Egypt-Japan University of Science
and Technology, New Borg El-Arab City, Alexandria, Egypt 3 - Electronic Materials Research Department, Institute of Advanced Technology and New Material, City of Scientific
Research and Technology Applications, New Borg El-Arab City 21934, Alexandria, Egypt [email protected]
Electrospun nanofibers with a high surface area to volume ratio have received much attention because of their potential applications for heavy metal and dyes removal. In this study, firstly, poly (Acrylonitrile-co- Styrene) (poly (AN-co-ST)) copolymer nanofibers with an average diameter form 80 nm to 1 μm were synthesized by solution polymerization of Acrylonitrile (AN) monomer and ST monomer crosslinker in the presence of Potassium persulfate (K2S2O8) initiator. Secondly, electrospinning of poly (AN-co-ST) copolymer in dimethyl formide (DMF) solvent have been investigated. Poly (AN-co-ST) nanofiber was modified and functionalized through introducing terminal carboxylic acid groups on the surface. The modified nanofiber was followed by Attenuated Total Reflectance Fourier Transformed Infrared (FTIR) measurements. The surface morphology and thermal behavior of the poly (AN-co-ST) nanofiber and their modified form were also characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) techniques further confirming modification.
P-042 MOLECULAR DESIGN OF POLYMER MATERIALS WITH QUADRATIC NONLINEAR OPTICAL RESPONSE: STRUCTURE-
PROPERTY RELATIONSHIP FOR EPOXY-BASED OLIGOMERS WITH BINARY ORGANIC CHROMOPHORES
A.I. Tukhbatulina, O.D. Fominykh, M.Yu. Balakina
A.E. Arbuzov Institute of Organic and Physical Chemistry of Kazan Scientific Center of Russian Academy of Sciences [email protected]
Polymer materials with nonlinear-optical (NLO) properties are probable candidates to be used in modulators and light signal converters. Application of such materials in optoelectronics is caused by their high quadratic NLO activity, structural variability, low dielectric permittivity, and fast response. Organic chromophores, which generally consist of donor and acceptor end groups and conjugated bridge, serve as molecular origin of NLO activity of polymer materials. Chromophores may be incorporated into the polymer matrix as guest molecules or as groups covalently attached to the main/side chain. Chromophore molecules have dipole moments about 10-15 D; when chromophore concentration is rather high, detrimental dipole-dipole interaction between them results in the decrease of quadratic NLO response. One of the ways to overcome this problem is to synthesize material based on oligomers with dendritic chromophore-containing fragments, realizing chromophores spatial separation. Promising approach is directed to the construction of composite NLO materials of the new type: chromophores-guests are introduced into host matrix, which is a chromophore-containing polymer; these are systems with binary chromophores. Here we present modeling of such composite materials consisting of epoxy-based oligomers (EAD) with dendritic fragments containing azochromophores, 4-amino-4’-nitroazobenzene - DR, and chromophores-guests, 4-amino-4’-tricyanoethenylazobenzene – TCE (see Figure 1).
Conformational search performed by Monte-Carlo technique with ММFF94s force field [1] allowed to determine the unique conformations for the following model systems: dimers EAD2 with two or four TCE-guests (EAD2-2 and EAD2-4); tetramers EAD4 with four or eight TCE-guests (EAD4-4 and EAD4-8). Electric characteristics (dipole moments and molecular polarizabilities) of a number of systems were calculated quantum chemically by TDHF//AM1 technique [2]. The performed modeling has shown that among the obtained conformers there is a sufficient quantity of those with spatially organized chromophores, the introduction of guest chromophores resulting in the structures of dendritic fragments most favorable from the point of view of NLO properties. In such molecular systems TCE-guests enter the region
between the dendron branches resulting in stacking-like arrangement of TCE and DR chromophores. These favorable structures are characterized by small values of both angles between chromophores in the dendrons and between dendritic fragments themselves. Such molecular systems are shown to have the enhanced values of first hyperpolarizability due to the formation of complexes with nonvalent interactions between chromophores. The amount of favorable structures increases with the oligomer chain length: from ca. 12% for EAD2-2 up to ca. 26% for EAD4-4. In the studied oligomers the optimal value of chromophores-guests per dendritic fragment producing maximal value of first hyperpolarizability was obtained to be 1:1. [1]. MacroModel, version 10.2, Schrödinger, LLC, New York, NY, 2013. [2]. Alex A. Granovsky, Firefly, http://classic.chem.msu.su/gran/firefly/index.html
NCH3
CH3
OHO O
OH
OO
O O
NN
NO2
NN
NO2
N N
n
a
N
N
N
CNNC
CN b
Figure.1. EAD oligomer unit (а); TCE chromophore (b).
P-043 BIREFRINGENCE IN FILMS OF POLYHETEROARILENE BASED ON 4,4`-DIAMINOTRIPHENYLAMINE AND 4,4`-(4,4`-ISOPROPYLIDENE-
DIPHENOXY)-BIS(PHTHALIC ANHYDRIDE), ORDERING OF THESE MOLECULES IN SURFACE LAYERS
N.A. Michailova1, N.A. Solovskaya2, G.I. Nosova2, A.V. Yakimansky2, G.M. Pavlov2
1 - St. Petersburg State University, St. Petersburg, Russia 2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Thermostable polyheteroarilene based on triphenylamine successfully used in optoelectronics devices. They have a high level of sensitivity and, thanks to its hole-conducting properties, are used as a transport layer, such as LED devices. This explains the interest in studying the properties of their films. The orientational order of anisotropic regions or ‘fragments’ of molecules in the surface layers of polyheteroarilene based on 4,4'-triphenylamine and 4,4'-(4,4'-isopropylidene-diphenoxy)-bis(phtalic angidride) (PTPR) films was evaluated by measuring the birefringence when polarized light passes
N
O
O
NO O
N
O
O
n
at different angles to the film surface [1, 2]. The phase difference between beams polarised in two perpendicular directions and forming an angle i with the polymer film surface is δ= (2B)sini; the coefficient of surface birefringence is B = [πNAρn3λ]((n2+2)/3)2((a|| – a)/M0)S0H0(1-exp(–H/H0)), S0 = (3<cos2θ>–1)/2 is the parameter of orientational order of molecular fragments with respect to the surface, where n is the refractive index of the polymer, is the wavelength of light, (1-2) is the difference between the main polarisabilities of the anisotropic chain element, Ms is the molar mass of statistical segment, is the average polymer bulk density, H0 is the effective thickness of the anisotropic surface layer, and H is the film thickness. The thicknesses of the films were varied in the range of (3-80) m. At high thicknesses the saturation of the birefringence effect is exhibited. Analyzing the films birefringence data the orientational order parameter S0 of PTPR fragments near the surface may be evaluated. The sign of S0 is negative and shows that the mean orientation angle of anisotropic PTPR chain fragments to the normal to the film surface is >54.7°. In other words, anisotropic chain fragments are predominantly parallel with respect to the surface. The data are compared with the results obtained previously for the birefringence of films from the polyheteroarilene of another structure [3]. [1] Cherkasov, A.N., Vitovskaya, M.G., Bushin, S.V. Vysokomol. Soedin., 1976, 18A, 1628–1634. [2] Grishchenko A.E., Pavlov G.M., Vichoreva G. A. Vysokomol. Soedin., 1999, 41 B, 1347-1350. [3] Pavlov G.M., Michailova N.A., Solovskaya N.A., Nosova G.I., Yakimanskii A.V. Optich. Journ”, 2014, 82, 2, 1-6.
P-044 COMPUTER SIMULATION STUDY OF ASSOCIATION BEHAVIOUR OF GRADIENT COPOLYMERS - NEW ALGORITHM FOR
RECOGNITION OF AGGREGATES
J. Kuldova, P. Kosovan, Z. Limpouchova, K. Prochazka Charles University in Prague, Department of Physical and Macromolecular Chemistry, Prague, Czech Republic
We present a computer simulation study of the association behavior of copolymer chains with gradient part and soluble tail of di�erent length. The formation of aggregates is promoted by solvent selectivity, concentration and length of soluble block. However in strongly selective solvents, when the solubility of the insoluble block is low, a non-negligible intermixing of di�erent segments destabilizes the gradient copolymer aggregate as compared with block copolymer micelles. The simulations suggest that insoluble segments from different aggregates often touch (but do not firmly interconnect individual particles) and temporary clusters of aggregates are formed. This significantly hinders the classification of individual aggregates according to the most often used criterion: two copolymers are considered to constitute an associate when exist at least one interchain neighbor pair formed by insoluble segments. Therefore we developed and tested new algorithm for the recognition and classification of aggregates. This new algorithm and results from simulation of the behavior association gradient copolymers will be presented.
P-045 IONIC STRENGTH INDUCED VISCOELASTIC FLUID OF LECITHIN-BILE SALT MIXTURE IN AQUEOUS SOLUTION
Ch.-Y. Cheng, Sh.-H. Tung
Institute of Polymer Science and Engineering, National Taiwan University, Taipei, Taiwan [email protected]
We found a new route for the formation of polymer-like micelles in lecithin-bile salt mixtures aqueous solution system that are long enough to impart viscoelasticity and the magnitude of zero-shear viscosity increases by 3 orders. The polymer-like micelles can form transient entangled networks that transform low-viscosity lecithin solution into viscoelasticity solution. This is the first report for the rheological properties of lecithin-bile salt mixtures in aqueous system. The molar ratio B0 of the lecithin-bile salt mixture plays the key role in the influence of the shape and the size of micellar structures, the mixtures in a small range of molar ratio can form long polymer-like micelles which is induced by increase of ionic strength. In contrast, bile acids can’t help lecithin to dissolve in aqueous solution and don’t show similar behaviors. We also found that the inducing efficiency of added salts are different, multivalent cation has higher inducing efficiency than univalent cations. We utilized small angle X-ray, neutron scattering and rheometer to analyze the structure of micelle, all the scattering and rheology data show the structure of lecithin-bile salt micelle are cylindrical with specific molar ration and ionic strength. This work gives prominence to the important of fluid and self-assembly behaviors of bio-surfactants in living system.
P-046 AMPHIPHILIC DIBLOCK COPOLYMER IN AN IONIC LIQUID
L.V. Zherenkova1, P.V. Komarov2 1 - Tver State University, Tver, Russia
2 - Institute of Organoelement Compounds, RAS, Moscow, Russia [email protected]
Ionic liquid/block copolymer systems are an extensively studied class of new functional materials that self-assemble on the nanometer scale. Ionic liquids (ILs) have been called “designed solvent” because of the tunability of solvation properties by choice of chemical structure of the cation and anion. In the present work, the structural properties and phase behavior of IL/block copolymer systems are investigated using the polymer integral equation or PRISM (polymer interaction site model) theory. The method has been shown to be effective in the weak and intermediate segregation regimes. The self-assembly of semidilute diblock copolymer in an ionic liquid is explored as encoded in small-angle partial scattering structure factors. Particular emphasis is placed on the region above the order–disorder transition and below the spinodal line, where a disordered phase of micelles is observed. The mean-field spinodal temperature TS is estimated via high-temperature approximation as a function of copolymer concentration at two different lengths of cationic tail. The influence of the length of cationic tail on dependencies of TS and the order–disorder transition temperature, TODT, on the copolymer concentration is investigated. Acknowledgements: Financial support from the RFBR (Project No. 12-03-00283-а).
P-047 AGGREGATIVE BEHAVIOR OF MULTIBLOCK-COPOLYMERS IN ORGANIC SOLVENTS OF VARIOUS SELECTIVITY
E.V. Chernikova, D.V. Vishnevetsky, E.A. Lysenko, A.V. Plutalova
Polymer Chair, Faculty of Chemistry, Lomonosov Moscow State University, Moscow, Russia [email protected]
Recent developments in polymerization techniques, including controlled radical polymerization, significantly extend the spectrum of macromolecular architectures available for self-assembly investigations. The more complicated is polymer architecture the more versatile is expected to be its behavior, both in solids and in solutions. Numerous publications are devoted to controlled synthesis of amphiphilic diblock- and graft-copolymers (including polymer brushes) and their hydrodynamic properties in different solvents. Recently we have reported about controlled synthesis of amphiphilic multiblock terpolymers based on polyacrylic acid (PAA), polystyrene (PS) and poly(n-butyl acrylate) (PBA) by means of reversible addition – fragmentation chain transfer polymerization. The synthesized block-copolymers differ by the sequence and molar/weight fraction of constituent blocks (Table 1). In current research we present the results of dynamic light scattering investigations of aggregative behavior of these copolymers in various organic solvents with different polarity and thermodynamic quality towards each of the blocks. Table 1. Multiblock-copolymer structure and composition.
Molar/weight fraction Block-copolymers styrene n-butyl acrylate acrylic acid
I PSPBAPAASC(=S)SPAAPBAPS PSSC(=S)SPAAPBAPS
0.25/0.28 0.21/0.30 0.53/0.42
II PSPBASC(=S)SPBAPAAPS PSSC(=S)SPBAPAAPS
0.27/0.27 0.44/0.53 0.29/0.20
III PAAPBAPSSC(=S)SPSPBAPAA PAAPSSC(=S)SPSPBAPAA
0.68/0.69 0.16/0.20 0.16/0.11
IV PAAPSPBASC(=S)SPBAPSPAA PAAPSSC(=S)SPBAPSPAA
0.45/0.43 0.38/0.45 0.17/0.11
Tetrahydrofuran ( = 7.6) being a good solvent for PS and PBA, while poor solvent for PAA, causes the aggregation of multiblock-copolymer macromolecules. Nevertheless, similar results have been observed in N,N-dimethylformamide ( = 36.7) or dioxane ( = 2.2), which are good solvents for PS, PBA, and PAA. Thus, aggregation of multiblock copolymers is characteristic feature of their solutions independently from solvent thermodynamic quality. The effective hydrodynamic radii of aggregates vary within the range 80 – 130 nm. The sequence of the blocks and their weight fraction has no influence on the aggregative behavior of block-copolymers. The scattering intensity increases linearly with the growth of polymer solution concentration, the aggregates average size is kept constant within the temperature interval 25 – 600C. The reasons of aggregative behavior of multiblock-copolymers in organic solvents are discussed. This work was supported by Russian Foundation for Basic Researches (project No 14-03-00155 и 14-03-00142).
P-048 STRUCTURE AND GAS TRANSPORT PROPERTIES OF POLYBENZOXAZINONEIMIDES WITH BIQUINOLINE UNITS IN THE
BACKBONE
G.A. Polotskaya1, N.S. Guliy1, M.Ya. Goikhman1, I.V. Podeshvo1, L. Brozova2, Z. Pientka2 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr.31, Saint-Petersburg, 199004,
Russia 2 - Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky sq.2, Prague 162 06, Czech
Republic [email protected]
Membrane technology has been currently used for the purification, concentration, and separation of gas and liquid mixtures. The range of commercial membranes is limited. Therefore, the development of new polymers for membranes with high performance and selectivity is of scientific and practical significance. Polymers of heteroaromatic structure are attractive materials for the application in membrane technology due to their high selective properties, chemical and thermal stability. In the present work polybenzoxazinoneimides (PBOI) which consists of polyimide and polybenzoxazinone fragments and, furthermore, contains biquinoline units in the backbone were under study. The essential value of PBOI is the hydrolytic stability of its prepolymer, imide-containing poly(amic acid) (PI-PAA). The aim of the work was to study structure and gas transport properties of membranes based on PI-PAA and PBOI and to compare them with properties of membranes based on the polymer-metal complexes PI-PAA-Cu(1) and PBOI-Cu(1). To obtain PI-PAA-Cu(1) polymer-metal complex, solutions of PI-PAA and CuCl in N-methylpyrrolidone were mixed for 1-2 min. PI-PAA dense film membranes were prepared by evaporation of N-methylpyrrolidone from the polymer solution on a glass plate. PBOI membranes were obtained by thermal treatment of the PI-PAA up to 250C; this procedure led to dehydration and benzoxazinone rings formation in the polymer backbone. Gas transport properties of four membranes was determined by laboratory high vacuum apparatus with a constant-volume permeation cell at 30C for H2, O2, N2, CH4, and CO2. It was established that gas permeability decreases in the following order: PI-PAA > PBOI > PI-PAA-Cu(1) > PBOI-Cu(1). The transformation of PI-PAA membranes in PBOI by heating to 250C leads to decreasing gas permeability. All membranes exhibit high selectivity in separation of the industrially significant gas pairs H2/N2, O2/N2, CO2/CH4, and CO2/N2. Membranes based on polymer-metal complex exhibit the highest selectivity. Finally, both permeability and selectivity were plotted on the Robeson’s diagram in order to determine the position of our polymers among the known gas separation membranes.
P-049 AMPHIPHILIC ALTERNATING SEMI-FLUORINATED COPOLYMERS AND THEIR NANOPARTICLES IN WATER
E.R. Gasilova1, S.D. Zaitsev2, Yu.D. Semchikov2
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St._Petersburg, Russia 2 - N.I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
Polymer-based nanoparticles (PBN) have been extensively investigated in recent years as drug delivery systems. PBN can be obtained by nanoprecipitation, e.g. by a dropwise addition of polymer solutions in organic solvent into non-solvent (water). Advantage of amphiphilic polymers is that their PBN do not need additional surfactants for colloidal stabilization1. Inclusion of fluorinated units into copolymers can promote higher PBN stability due to the fluorophobic effect. In the current work, PBNs were prepared from amphiphilic semifluorinated copolymers synthesized by RAFT polymerization with benzylthiobenzoate as a chain transfer agent2. The chemical structure of hydrophobic (1,1,1-3,3,3-hexafluoroisopropyl--fluorolacrylate) and hydrophilic (vinyl pyrrolidone) monomers composing the copolymers is presented in Fig. 1. Fig.1. Chemical structure of the monomers composing the alternating amphiphilic copolymers. We studied static (SLS) and dynamic light scattering of PBNs formed from alternating copolymers of molecular mass 41, 53, and 61 kg/mol. The copolymers were obtained at different conversions of RAFT polymerization. The apparent molecular mass Mapp of copolymers determined by SLS in ethanol solutions was found to be extremely sensitive to their compositional heterogeneity3. Comparison of Mapp with the molecular mass determined by size-exclusion chromatography2 (Mw
SEC) shows that the compositional heterogeneity of copolymers increases with conversion. In particular, Mapp is equal to Mw
SEC only at the earliest stage of RAFT copolymerization, indicating the compositional homogeneity of the copolymer with Mw
SEC = 41 kg/mol. High structure-sensitive ratio of the radius of gyration (Rg) to the hydrodynamic radius (Rh), Rg/Rh > 2.05, points out that the copolymers adopt rodlike conformations3. Nanoprecipitation method needs two solvents of different quality – a bad and a good one. SLS measurements showed that the second virial coefficient in ethanol solutions is positive, e.g. ethanol is a good solvent for copolymers. Copolymers with Mw
SEC = 41 and 53 g/mol do not dissolve in water, whereas the copolymer of Mw
SEC = 61 kg/mol forms large micelles. PBNs in the range of 40 Rh 50 nm were prepared by dropwise addition of ethanol solutions into water. The range of structure-sensitive ratios 0.8 Rg/Rh < 1 indicates the spherical form of PBN colloids. The stability of PBN colloids is studied. 1. Ph. Legrand et. al, International Journal of Pharmaceutics 344 (2007) 33. 2. S.D. Zaitsev et. al, Polymer Science B 51 (2009) 84. 3. E.R. Gasilova et. al, International Journal of Polymer Analysis and Characterization, 18 (2013) 510.
H2C CH
NO
H2C CF
C O
O
CH
CF3F3C
P-050 CONFORMATIONAL PROPERTIES AND INTERACTIONS OF HYDROPHOBIC PH-SENSITIVE POLYELECTROLYTE STARS
O.V. Rud1, T.M. Birshtein2
1 - Institute of Macromolecular Compounds of RAS, Saint-Petersburg, Russia 2 - Institute of Macromolecular Compounds of RAS, Saint-Petersburg, Russia; Facility of Physics, St. Petersburg State
University, Saint-Petersburg, Russia [email protected]
The change in conformation of the two hydrophobic pH-sensitive polyelectrolyte stars during their mutual approach was studied using the numerical Scheutjenes–Fleer Self–Consistent Field method. All the monomer units of the homopolymeric stars include the ionogenic and the hydrophobic group. If the hydrophobicity rate of these groups is high enough and the solution ionic strength is sufficiently low, a separately taken star constitutes a two-phase unimolecular micelle (quasi-micelle). The quasi-micelle is formed by the division of star arms into two groups, one of uncharged arms forms a dense core, another one of passing through the core arms forms the charged corona. As two stars in such conformation approach each other, when their coronas overlap some coronal arms lose their charge and experience transition to the core phase. Then as the cores get in contact, two quasi-micells merge into one unified. The interaction free energy of two stars is a non-monotonic function of the distance D between their centers. At high D it increases, while stars get closer. At low D there is the local minimum, corresponding to the unified quasi-micelle state. The character of interaction is strongly dependent on the solution salinity. At low ionic strength the equilibrium configuration provides the free energy global minimum at small D (unified micelle), while at relativelly high ionic strength the minimum is at infinity (two separated stars). At high salinity a separately taken star has fully swollen conformation. However, if the salinity is only slightly above the threshold of microphase segregation, the transition to the quasi-micellar state may be induced by the stars approaching. The study of the single star interaction with flat hydrophobic surface has shown, that this transition could be induced by any of the spatial constraints imposed on the star corona. The interaction curves for the quasi-micellar star and the surface showed again the repulsion at high D and attraction at low D. The increase in salinity makes part of a hydrophobic core phase lower, so the attraction becomes weaker and the repulsion becomes stronger. At highest salinity there is again the repulsion for all D. This work has been supported by the Russian Foundation for Basic Research (project No. 12-03-31649 and No. 11-03-00969-a).
P-051 INFLUENCE OF THE BOND TYPE BETWEEN HYDROPHILIC AND HYDROPHOBIC FRAGMENTS ON SELF-ORGANIZATION OF PEG
CONJUGATES
L.I. Kaberov, N.V. Girbasova, A.Yu. Bilibin Saint-Petersburg State University, Institute of Chemistry, Saint-Petersburg, Russia
Influence of the bond type between fragments of different nature in amphifilic PEG conjugates on their ability to formation of ordered phases in solid state as well as self-organization in solutions was systematically studied. We used methoxy polyethyleneglycols (MPEG) amines (550 and 2000), PEG (2000) bis-amine and their conjugates with dendritic derivatives of L-aspartic acid with peripheral amino groups as hydrophilic components and dodecyl carbonic acid and dodecyl ester of sulfuric acid as hydrophobic components. Ionic complexes were obtained by mixing solutions of components followed by removing the solvent. Also the analogous covalent conjugates - dodecyl carboxylic acid amides and esters have been synthesized.. Thus three series of compounds with rigid amide bonds, more flexible ester bonds, week and strong ionic bonds were studied. Self-organization of the conjugates in solution was studied by dynamic light scattering (DLS), in a condensed state - by differential scanning calorimetry (DSC), polarizing optical microscopy, small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). In all linear conjugates the crystal lattice of PEG is retained and tails C12 are assumed to be located in its cavities. The sharpest reflexes in small-angle region are observed for amides, less sharp for esters and ionic complexes. Thermograms has a single melting peak (about 50 ºC), which is reproduced in the second heating run. In aqueous solutions of ionic complexes large aggregates are observed mainly unlike covalent analogs. For all branched conjugates the typical for crystalline PEG reflexes in wide-angle region are absent. Unlike covalent conjugates ionic complexes have several reflexes in the small-angle region, which indicates formation of ordered supramolecular structures. This is consistent with their DSC curves, where one can see a several peaks corresponding to the melting or restructuring of supramolecular structures. Branched amides do not melt until the temperature of thermal degradation, form gels in low-polarity solvents. Branched esters are perfectly soluble in low-polarity solvents even such as diethyl and petroleum ether. They as well as ionic complexes do not form gels. Ionic complexes with dodecyl carboxylic acid are not enough stable in water for obtaining correct results of the study. Ionic complexes with dodecyl ester of sulfuric acid, obtained in water, retain LC ordering typical for the acid itself. The structure of some complexes in the condensed state can depend on the conditions of preparation of the complex. This work was supported by RFBR (project № 12-03-00746 a). The study was conducted in RC SPSU "Methods of analysis of the composition of matter" (SAXS and WAXD), "Thermogravimetric and calorimetric methods of study" (DSC), “Diagnostic Center of functional materials for medicine, pharmacology and nanoelectronics” (DLS).
P-052 MATRIX POLYMERIZATION OF SURFACTANT MICELLES
A.A. Lezov1, P.A. Fetin2, A.S. Gubarev1, L.I. Akhmadeeva1, I.M. Zorin2, A.Yu. Bilibin2 1 - The Physical Faculty SPbSU, Saint-Petersburg,Russia 2 - SPbSU Faculty of Chemistry, Saint-Petersburg,Russia
An important problem in polymer physics and chemistry is to obtain self-organizing systems, which structural elements have a narrow size distribution and retain their properties under variation of external conditions. Polymerization of surfactants is able to fix the structure of the micelles, or to obtain a macromolecule with monomers based on ionic surfactants. Such polymers may possess properties of amphiphilic systems and be in demand in various applications. Matrix polymerization of monomers included in polyelectrolyte complexes, as a special case of chemical transformation in structurally organized systems is a powerful tool for creating new functional materials. Dynamic, static light scattering, high-speed sedimentation, viscometry and atomic force microscopy experiments were carried out to determine molecular characteristics of initial matrixes and their complexes before and after polymerization. Samples of linear polyelectrolyte (PE) sodium poly-2-acrylamido-2-methyl-1-propanesulfonate(PAMPS-Na) were used as a matrix. It was obtained from sodium 2-acrylamido-2-methyl-1-propanesulfonate by free radical polymerization in water. Coefficients and exponents in Mark–Kuhn–Houwink empirical equations were experimentally determined for PAMPS-Na samples in water with 0.05M NaCl addition. Calculated exponent ν, binding end-to-end distance with degree of polymerization, was about 0.6. This fact show that 0.05 M NaCl is thermodynamically good solvent for PAMPS-Na. Cationic surfactant 11-(acryloyloxy)undecyltrimethylammonium Bromide (AUTAB) has double carbon-carbon bond and is able to be polymerized in solution or being bounded in complex. Polyelectrolyte – surfactant complexes (PEsC) were obtained by mixing solutions of PAMPS and AUTAB at 1:1 stoichiometric ratio in 0.05 M NaCl. At low concentrations of components there is no phase separation occurs. Spectrums of diffusion coefficients for PEsC solutions are characterized by two main peaks. The first is close to the value obtained for initial matrix and second is up to ~10 times lower than the first one. Interpolyelectrolyte complexes (IPECs) pAMPS-pAUTAB were prepared by free radical polymerization of PEsC with K2S2O8 or 2,2′-Azobis(2-methylpropionamidine) dihydrochloride at 60 C. Spectrums of diffusion coefficients obtained in IPEC solutions exhibit one main peak with value of diffusion coefficient about 5 times lower than its value for initial matrix. The authors are grateful to the Russian Foundation for Basic Research (Grants no. 14-03-31861 13-03-00474) for financial support. Sedimentation coefficients were determined on apparatus of Center for diagnosis of functional materials for medicine, pharmacology and nanoelectronics St. Petersburg State University.
P-053 STIMULI-RESPONSIVE REVERSIBLE HYDROGELS FROM TRIBLOCK POLYELECTROLYTES AND POLYAMPHOLYTES
M.A. Dyakonova1, N. Stavrouli2, M.-T. Popescu2, K. Kyriakos1, I. Grillo3, M. Philipp1, S. Jaksch4,
C. Tsitsilianis2, C.M. Papadakis1 1 - Fachgebiet Physik weicher Materie, Physik-Department, Technische Universitat Munchen, James-Franck-Str. 1,
85748 Garching, Germany 2 - Department of Chemical Engineering, University of Patras, 26504 Patras, Greece
3 - Large Scale Structures Group, Institut Laue-Langevin, 6, rue Jules Horowitz, 38042 Grenoble, France 4 - Forschungszentrum Julich GmbH, Julich Centre for Neutron Science at MLZ, Lichtenbergstr. 1, 85747 Garching,
Germany [email protected]
We study the structure and conformational properties of charged stimuli-responsive hydrogels from two chemically related triblock copolymers: polyampholyte P(AA-b-2VP-b-AA) (P2VP and PAA are poly(2-vinylpyridine) and poly(acrylic acid)), and its precursor with the same block lengths – triblock polyelectrolyte P(tBA-b-2VP-b-tBA) (PtBA is poly(tert-butylacrylate)). The difference in gelation ability and final properties of the hydrogels of these two polymers were ascribed to the different mechanisms of aggregation (Stavrouli et al., Polymer 2008, 49, 1249). Rheological and small-angle neutron scattering studies revealed differences in the structure of the hydrogels at pH 3 in dependence of the nature of the outer blocks – pH dependently ionized PAA blocks or hydrophobic PtBA blocks. The first cause electrostatic attractive interactions with the positive P2VP blocks resulting in the formation of a gel network, whereas the latter ones aggregate by forming flower-like micelles. Quaternization of the middle P2VP block in P(AA-b-2VP-b-AA) allowed us to study a system with permanent positive charge on the middle PQ2VP block but with variable value of positive charge in the system at different pH values. The variation of the charge imbalance on the chain has a strong influence on the morphological properties of obtained hydrogel P(AA-b-Q2VP-b-AA). Thus, a low charge imbalance causes aggregation of the chains in large globular structures due to the electrostatic interactions between oppositely charged blocks, while shifting to a higher imbalance these structures break up and rearrange in a three-dimensional network. These results demonstrate the stimuli-responsive behavior in these systems. We thank CompInt Program for financial support. We thank DAAD and IKY for financial support of mutual visits in the framework of the IKYDA program.
P-054 TEMPLATE POLYMERIZATION OF IONIC MONOMERS IN MICELLAR SOLUTIONS OF SODIUM DODECYLSULFATE AND
PROPERTIES OF THE RESULTANT COMPLEXES
Le Thi Doan Trang, E.G. Dukhanina, Yu.V. Shulevich, A.V. Navrotskii, I.A. Novakov Volgograd State Technical University, Volgograd, Russia
During recent decades, polyelectrolyte-surfactant complexes attract constant interest due to increasingly expanding application: from the flocculation and wastewater treatment to functional additives to detergents and cosmetics. Therefore, polyelectrolyte-surfactant complexes with new or specific characteristics, their properties and novel synthetic ways are of great interest. An interesting and perspective way of synthesis of polyelectrolyte-surfactant complexes is template polymerization of ionic monomer in micellar solution of oppositely charged surfactant. Trimethyl(methacryloyloxyethyl)ammonium methyl sulfate (M1), N,N-dimethyl-N-ethyl(methacryloyloxyethyl)ammonium bromide (M2) and [N-benzyl-N,N-dimethyl-N-(methacryloyloxyethyl)] ammonium chloride (M3), which were used as monomers, were obtained via the alkylation of freshly distilled amino ether with dimethyl sulphate, benzyl chloride or brome-ethane in a medium of acetone. The synthesized monomers were recrystallized from acetone and dried in a vacuum. Sodium dodecylsulphate (SDS) was used as surfactant. Polymerization was performed in the isothermal regime under argon at 30°C. Tertbutylperoxipropanol-2 was applied as an initiator. The molar ratio between monomer and surfactant was varied in a wide range. The complex formation was studied by turbidity measurements. The composition of complexes (Z) was characterized as the ratio between the molar concentration of SDS and polyelectrolyte in the system (Z = [SDS]/[polyelectrolyte]). Z was changed from zero (the pure polyelectrolyte solution) to one (the stoichiometric complex). It was defined that the highest composition of the reaction mixture at which the system remains transparent (turbidity is close to zero) corresponds to the limiting composition (Zlim) of the water-soluble complexes relevant to the maximum surfactant content in the system at which the complexes remain soluble in aqueous media. Polymerization of synthesized monomers in a micellar solution of SDS, in dependence on a molar ratio between monomer and surfactant, leads to formation soluble and insoluble polyelectrolyte-surfactant complexes. For instance, polymerization of M2 in 0.1 M SDS solution and molar ratio monomer-surfactant from equimolar to fivefold excess leads to formation of stoichiometric polyelectrolyte-surfactant complexes. Increasing this ratio to sevenfold excess of monomer and higher leads to formation of water-soluble complexes. An increase in monomer concentration implies an increase in surfactant concentration, and because of this, formation of stoichiometric complexes is complicated due to diffusive restrictions. The resultant complex can be considered as a block copolymer which includes two types of polymer fragments: fragments which were grown in solution and fragments which were grown under micelle control. The range of existence of soluble or insoluble complexes significantly depends on monomer hydrophobicity. Thus, the surfactant concentration of 0.2 M applies only nine-fold excess of a M3 to obtain water-soluble polymerization products, but the surfactant concentration of 0.5 M requires a fourfold excess of M3 to obtain water-soluble product. Moreover, the resultant complexes are non stoichiometric. Apparently, it is happened because of another mechanism of formation of polyelectrolyte-surfactant complexes, because for M3 monomer polymerization is accompanied coacervation phenomenon. The obtained data show that the polymerization of ionic monomers in the presence of oppositely charged surfactants is an alternative way of preparation of polyelectrolyte–surfactant complexes. And it make possible to obtain water-soluble complexes noticeably enriched with surfactant ions, as compared to the complexes formed in the common way. The complexes obtained by template polymerization are very stable and include more non – equilibrium defects in their structures than complexes obtained by mixing. The obtained results are important for complex applications, for instance, in flocculation processes. The study was supported by Russian Foundation for Basic Research (grant 13-03-00822).
P-055 INTERACTIONS IN TRIPLE SYSTEMS CONTAINING CROSS-LINKED POLYELECTROLYTE, STAR-SHAPED POLY(ACRYLIC ACID)
AND LINEAR POLYCATION
T.V. Panova, A.B. Zezin Lomonosov Moscow State University, Moscow, Russia
The competitive reactions in triple systems containing anionic gel, star-shaped poly(acrylic acid), and linear polycation were studied. Cross-linked sodium poly(acrylate) or sodium poly(2-acrylamido-2-methylpropanesulfonate) were used as anionic networks. Star-shaped poly(acrylic acid) ((PAAN)Х, where N~100 is an arm degree of polymerization, and X is a number of arms) with 8 and 21 arms were used. Linear poly(N-ethyl-4-vinylpyridinium bromide) or poly(2,5-ionen bromide) were used as polycations. Non-stoichiometric complexes (NIPECs) of (PAAN)Х and linear polycations were obtained. The composition of NIPECs, φ, was equal to 0.12-0.3, where φ is the ratio of mole amount of positively charged groups to the mole amount of negatively charged carboxylic groups in a complex. NIPECs are soluble in aqueous media due to the excess of negatively charged groups of star-shaped polyanion. It was shown that sulfo-containing network can substitute star-shaped poly(acrylic acid) in NIPECs with a formation of stoichiometric complex in a gel phase. However, when both star-shaped and cross-linked polyanions are of the same chemical nature, the substitution reaction does not proceed. Moreover, under immersion of stoichiometric complex containing a carboxylic network and linear polycation into the solution of free (PAAN)Х, the transfer of linear polycations from the gel to the star-shaped polyacrylic acid in the surrounding solution is observed. Thus, the chemical nature of the cross-linked and star-shaped polyelectrolytes determines the character of distribution of linear polycation between a gel and star-shaped polyanion. This work was supported by Russian Foundation for Basic Research (project № 12-03-00705)
P-056 PHASE TRANSITIONS, SELF-ORDERING AND RHEOLOGICAL PROPERTIES OF LIQUID CRYSTAL NANOSYSTEMS IN MAGNETIC
FIELD AND IN ITS ABSENCE
S.A. Vshivkov, E.V. Rusinova, A.G. Galyas, T.S.A. Soliman Ural Federal University, Chemical department, Ekaterinburg, Russia
The liquid crystals combining properties of a liquid and an anisotropic crystal substance play an important role in a science and engineering. Molecules of cellulose and its derivatives have a rigid helical conformation, stabilized by intramolecular hydrogen bonds. Therefore the macromolecules of these polymers are capable to be ordered at dissolution and form liquid crystals of holesteric type. Phase diagrams of solutions of some cellulose derivatives are known. However, little is known about the effect of a magnetic field on the structure and viscosity of polymer solutions. The systems cyanoethyl cellulose (CEC) – DМАА, CEC –DМF, hydroxypropyl cellulose (HPC) – ethanol, HPC – DМАA, HPC – DМF, HPC – water, ethyl cellulose (EC) – ethanol, EC – DMAA, HPC – ethyleneglycol, hydroxyethyl cellulose (HEC) – water, HEC – DMF and HEC – DMAA were studied in the presence and absence of a magnetic field. The phase transition temperatures Тph and the type of phase transition were estimated by the cloud - point method and with the help of polarization photoelectric setup. The size r of the light scattering particles was estimated via the turbidity spectrum method. The solution viscosity was determined on a Rheotest RN 4.1 modified rheometer. The effect of a magnetic field on the solution properties was studied with the use of two magnets, which induces a magnetic field with an intensity of 3.7 kOe and field lines directed perpendicularly to the rotational axis of a rotor and with an intensity of 3.6 kOe and field lines parallel to the axis of rotor rotation. The phase diagrams of the systems were determined. The magnetic field leads to the increase of the phase transition temperatures. The concentration dependence of ΔТ = Tph – Tph0 is described by curve with maxima (Tph and Tph0 are the temperatures of the liquid crystalline phase transition in the presence and absence of magnetic field, respectively). Application of the magnetic field is shown to be accompanied by an increase in the additional assembly of macromolecules, as is evident from a gain in the radii of light scattering particles. The concentration dependences of Δr = r – r0 also are described by curves with maxima (r and r0 are the radii of particles after and before magnetic field treatment, respectively). In the presence of a magnetic field, the long chains of macromolecules are oriented in parallel with field lines. Such an orientation is associated not with the presence of permanent magnetic domains but with the molecular diamagnetic anisotropy of macromolecules. As a result, supramolecular particles are formed, especially in the vicinity of the region of LC phase transition. The magnetic field leads also to the increase in viscosity of solutions. The results were used to plot the concentration dependence of η/η0, where η and η0 are the viscosities of solutions in the presence and absence of a magnetic field, respectively. In this case, the values of viscosity corresponding to low shear rates were chosen because the concentration dependence of viscosity at low shear rates is typical for anisotropic systems. In the investigated composition range, the values of η/η0 are above unity and the concentration dependence of this value, like that of the radii of supramolecular particles described by a curve with a maximum. This work was supported by the Russian Foundation for Basic Research, project no. 2-08-00381-a.
P-057 PHASE EQUILIBRIUM IN PE – PS AND PBA – PS SYSTEMS
U.V. Nikulova1, A.E. Chalykh1, A.A. Shcherbina1, E.V. Chernikova2 1 - 1A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia
2 - M.V. Lomonosov Moscow State University, Chemical Department, Moscow, Russia [email protected]
The comparative research of polystyrene (PS, *=19.1 (MJ/m3)1/2) solubility with polyethylene (PE, =16.0 (MJ/m3)1/2) and poly(n-butyl acrylate) (PBA, =18.3 (MJ/m3)1/2) was conducted by means of optical interferometry method in wide temperature range. PE and PBA had constant molecular weight 1.0 and 35.0 kDa respectively, but molecular weight of PS varied from 0.8 to 30.0 kDa. Results of researches are presented in Fig. 1 and 2. It is obvious that both systems with Δ 3.1 and 0.8 MJ/m3 are characterized by diagrams with Upper Critical Solution Temperature (UCST). The location of a critical point is defined by a ratio of components molecular weight and corresponds to critical concentration φcr calculated by the Flory-Huggins theory. It is interesting to note that PBA is more compatible with PS than PE. For PS with Mn=2.33 and low-molecular PE we observe a limited compatibility at the right and the left sides of diagram, whereas the same PS with high-molecular PBA is dissolved completely at temperatures over 450 K. Values of pair interaction parameter () of components and its critical value (cr) were calculated based upon compositions of coexisting phases of both systems. Temperature dependence of for PE – PS system has concave character, whereas for PBA – PS system is linear one. At that comparison of PS with Mn=2.33 showed that numerical values of change within 0.108 to 0.151 range at temperature decrease from 480 to 390 K for PE system (cr=0.0717), and within 0.043 to 0.075 range at temperature variation from 430 to 370 K for PBA system (cr=0.0369). The obtained information was used for prediction of phase structure of PE and PBA block-copolymers with PS.
Fig. 1. Phase state diagrams of PE – PS system. Molecular weight of PE is 1.0 kDa and of PS are 0.82 (1), 1.2 (2), 2.33 (3) and 9.0 kDa (4).
Fig. 1. Phase state diagrams of PBA – PS system. Molecular weight of PBA is 35.0 kDa and of PS are 1.2 (1), 2.33 (2), 3.6 (3), 4.1 (4) and 30.0 kDa (5).
*Properties of polymers: their correlation with chemical structure : their numerical estimation and prediction from additive group contributions/ by D. W. van Krevelen. – 4th, completely rev. ed./ K. te Nijenhuis. ISBN978-0-08-054819-7 Study is supported by Russian Foundation of Basic Research, Projects No. 14-03-00390.
P-058 POLYACID CONFORMATION INFLUENCE ON POLYANILINE SYNTHESIS AND ITS PROPERTIES
O.D. Omelchenko1, O.L. Gribkova1, A.A. Nekrasov1, V.F. Ivanov1, V.A. Tverskoy2,
A.V. Vannikov1 1 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia
2 - M.V. Lomonosov Moscow State University of Fine Chemical Technologies, Moscow, Russia [email protected]
Up to date, polyaniline remains one of the most studied conductive polymers because of the wide range of its possible applications. We focus our study on chemical oxidative aniline polymerization in the presence of polyelectrolytes due to the obvious benefits of such synthesis method compared to the conventional polyaniline synthesis in the inorganic medium. Among these advantages the following could be mentioned: the high rate of this process at very low concentrations of reagents and the production of water-soluble/ water-dispersible electroactive polyaniline with a more ordered structure, the possibility to modify the structure of the polymer with the purpose to change its optical and electrical properties. Furthermore, due to introducing polyacid into the complex, the forming polyaniline is self-doped; as a result, it retains its properties at high pH (even at alkaline pH). Here, we report the results of investigation of the influence of polymeric acid conformation on aniline polymerization and properties of obtained polyaniline-polyacid complexes. As a polyelectrolyte we chose poly-(2-acrylamido-2-methyl-1-propanesulfonic acid), PAMPSA, a commercial Aldrich product. The PAMPSA is known to be flexible-chain polyacid therefore the chain extension occurs under dilution. Thus, the conformation of such flexible-chain polyacid is dependent on its concentration. In the present work, we varied the aniline: polyacid molar ratio in wide range, namely 1:1 to 1:10 mol/g-eq. It is shown that the higher polyacid concentration in the reaction medium, the slower aniline polymerization. However, the electronic structure of polyaniline remains the same in all cases. It is demonstrated by UV-vis-spectrophotometry and ESR-spectroscopy methods that polyacid chain conformation influences the polyaniline chain packaging. The conductivity of obtained polyaniline – PAMPSA complexes increases with decreasing polyacid content. It is likely to be connected with different interchain contact between polyaniline due to insulating polyacid presence. We are grateful to the Russian Foundation for Basic Research (grant No. 14-03-01137_а and 12-03-01087_а) for financial support.
P-059 CONFORMATIONAL AND SELF-ASSEMBLY EFFECTS IN POLYANILINE OLIGOMERS
O.E. Bogomolova, A.A. Savelyeva, V.G. Sergeyev
M.V. Lomonosov Moscow State University, Faculty of Chemistry, Moscow, Russia [email protected]
Polyaniline oligomers – low molecular weight models of polyaniline, one of the most interesting conducting polymers. Acid doping (protonation) of polyaniline leads to generation of conductive salt form. Conformational and self-assembly effects in doped polyaniline can influence its conductivity, stability and other properties. According to complex structure of polyaniline some of these effects are easier to study on model compounds. Here we present the study of trianiline, tetraaniline and mixture of longer polyaniline oligomers doped by various acids in different solvents. It was found that acid doping of tetraaniline or polyaniline oligomers mixture with polyacids (poly(4-styrenesulfonic acid) or poly(2-acrylamido-2-methyl-1-propane-sulfonic acid)) in DMSO lead to appearance of a new absorption band in UV-vis-NIR spectra. This band is intensive, quite sharp in case of tetraaniline, broader in case of oligoaniline mixture and characterizes by the maximum at the wavelength of more than 1000 nm. The result is nearly the same for both polyacids. The same spectral changes appeared to be achievable by addition of large excess (orders of magnitude) of low-molecular weight acids (camphorsulfonic, dodecylbenzene sulfonic, HCl) to tri- or tetraaniline. Addition of low-molecular weight electrolyte (NaCl) lead to opposite changes in spectra of doped tetraaniline. In case of polymeric dopant intensity of the long wavelength absorption band decrease with the increase of NaCl concentration, while in the case of low molecular acid – increase. This long wavelength absorption band in UV-vis-NIR spectra of polyaniline oligomers is similar to one observed for highly conductive well ordered polyaniline. The effect can be explained by conformational changes (stretching) of oligoaniline molecules or, less probably, by self-assembly of oligoaniline molecules with J-aggregates formation.
P-060 PH-AND TEMPERATURE-SENSITIVE BEHAVIORS OF 2-(DIETHYLAMINO)ETHYL METHACRYLATE AND 2-DEOXY-2-
METHACRYLAMIDO-D-GLUCOSE RANDOM COPOLYMERS IN SOLUTION
T.N. Nekrasova, L.N. Andreeva, Yu.I. Zolotova, M.A. Bezrukova, R.T. Imanbaev,
O.V. Skorbunova, O.V. Nazarova, V.D. Pautov, E.F. Panarin Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol’shoi pr. 31 (V. O.), St. Petersburg, 199004
Russia [email protected]
During the last two decades the water-soluble pH- and temperature-sensitive (co)polymers have attracted considerable attention from both fundamental and applied research due to the possibility of wide varying of conformational and functional properties. Stimuli-responsive copolymers are an interesting class of copolymers because their physical and chemical properties can be adjusted by external stimuli, such as temperature, pH, ionic strength, light, etc. Water-soluble temperature responsive polymers are one of the most appealing stimuli-responsive species. They undergo a fast and reversible phase transition in aqueous solutions at the lower critical solution temperature (LCST). Besides the temperature-triggered stimulus, pH is another important triggering signal for phase transitions in polymer aqueous solution. Both stimuli are important environmental factors in biomedical systems, especially in controlled drug delivery systems. Amphiphilic stimuli responsive block copolymers attracted much more attention than random ones. At the same time the synthesis of random copolymers is usually more easy than that of block copolymers and statistical copolymers may be used as stimuli responsive too [1]. In this work a series of random copolymers of 2-(diethylamino)ethyl methacrylate (DEAEMA) and 2-deoxy-2-methacrylamido-D-glucose (MAG) containing anthracene luminescent labels was synthesized by free radical copolymerization of DEAEMA, MAG and 9-anthrylmethyl methacrylamide in N,N-dimethylformamide solution. The polarized luminescence and flow birefringence methods were used for investigating thermo- and pH stimuli conformational transitions in copolymers. A significant difference of the stimuli-responsive behavior depending on DEAEMA units content in copolymers was observed (Tab.). For copolymer containing 40 mol. % DEAEMA units the LCST is near 36-38 oC and the LCST decreases with increasing content of DEAEMA. For all copolymers the temperature induced conformational transition is accompanied by increasing nanosecond relaxation times τ IMM characterizing the intramolecular mobility (IMM) of polymer chain. Table Parameters characterizing T-induced conformational transition in water.
τ IMM, ns DEAEMA,
mol % [η]*, dl/g
MsD* Ttr, oC lower LCST
higher LCST
60 0,53 120000 <15 - 95
40 0.50 162000 37 44 58
22 0.32 126000 >60 43 -
*[η] and MsD were determined in (0,1N HCl+0.1N HCl) aqueous solution [1] Zhang C., Maric M. Polymers. 2011. V. 3. № 3. P. 1398-1422. This work was supported by the Presidium of the Russian Academy of Sciences (Program no. 24 for Basic Research).
P-061 CARBOXYACYLATION OF CHITOSAN IN AQUEOUS SOLUTION AND SUSPENSION
A.A. Golyshev1, Y.A. Skorik2
1 - St.Petersburg State Chemical Pharmaceutical Academy, Analytical Chemistry Department, St.Petersburg, Russian Federation
2 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, St.Petersburg, Russian Federation [email protected]
Among naturally occurring polysaccharides, considerable attention has recently been focused on the polyaminosaccharide chitosan, the deacetylated derivative of chitin that is easily obtained at relatively low cost. Much interest has been paid to its biomedical, environmental, agricultural, food processing and other industrial applications. However, chitosan related applications are limited by its insolubility in water at pH higher than 6. The presence of reactive functional groups allows the various chemical modifications. A number of studies of chitosan have been aimed at chemical modification of the polymer with hydrophilic groups to improve its solubility across the whole pH range. Carboxyacyl groups represent useful hydrophilic substituents, as their ionization in the alkaline range improves the polymer solubility and may impart useful biological properties. The aim of this study is a systematic investigation of chitosan carboxyacylation using succinic and glutaric anhydrides in dilute acetic acid solutions and in aqueous suspension. Two general procedures were applied for the preparation of carboxyacyl chitosan derivatives: (1) the homogenous reaction of chitosan predissolved in 1% acetic acid solution with succinic or glutaric anhydride, and (2) the heterogenous reaction of chitosan aqueous suspension with correspondent anhydride. The influence of the following parameters on the reaction yield were studied: (a) the molar ratio of the reactants, (b) the reaction time, (c) the reaction temperature, and (d) the type of preactivation of the chitosan suspension. All products were characterized using 1H NMR and elemental analysis. It has been shown that acylation of chitosan using succinic and glutaric anhydrides under the reaction conditions used in this work proceeds exclusively at the amino group of chitosan resulted in the formation of N-succinyl- and N-glutaryl-chitosan, respectively. Such thorough exploration of the reactions under study will allow for suggestion of a convenient (in terms of reaction time and degree of substitution) procedure of the preparation of the desired products with particular degree of functionalization. In the near future, we plan to use these water-soluble chitosan derivatives to design the self-assembled nanoparticulate drug delivery systems and drug conjugates with potential for decreasing toxicity, improving stability, targeted delivery and bioavailability. Acknowledgment: Anton Golyshev is grateful to the Foundation for Assistance to Small Innovative Enterprises for the financial support.
P-062 MOLECULAR ORDERING OF POLY (N-METHYL-N-VINYL ACETAMIDE) MOLECULES IN SOLUTIONS AND IN FILMS
MONITORED BY BIREFRINGENCE METHODS
G.F. Kolbina1, N.A. Michailova2, I.I. Gavrilova3, E.F. Panarin3, G.M. Pavlov3 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences
2 - Fock Research Institute of Physics, St. Petersburg State University,ul. Ulyanovskaya 1, Petrodvorets, St. Petersburg, 198504 Russia
3 - Institute of Macromolecular Compounds, Russian Academy ofSciences, Bolshoy pr. 31, St. Petersburg, 199004 Russia
The polymers based on N-vinylamides are of considerable interest as new potential carriers of biologically active substances. However, in contrast to poly(N-vinylpyrrolidone) and poly(N-vinylcaprolactame), the conformational and molecular characteristics of noncyclic N-vinylamides are not enough investigated, for example, for poly(N-methyl-N-vinylacetamide) (PMVA),they are unknown at all. The birefringence methods are very sensitive to the peculiarities of the macromolecule structure. Flow birefringence (FB) of the PMVA aqueous solutions was studied in the considerable range of molar masses and concentrations. In previous hydrodynamic study [1] the value of the refractive index increment (n/c) in water solutions was determined as n/c = (0.15±0.01) cm3/g. Such high value of n/c means that the flow birefringence effect is determined not only by the proper optical anisotropy, but also be determined by the macroform effect. The change of sign of the reduced FB values [n]/[] were observed firstly by studying the FB of fractions of different molar masses, secondly by studying the FB of high molar mass fraction in the wide range of concentration. It was obtained that the anisotropy of the proper (intrinsic) optical polarizability of the PMVA segment (l - 2) is negative and is equal to (l - 2) = - 2010-25 cm3. This value is compared with the corresponding values obtained earlier in the literature for the macromolecules of similar structures [2]. Knowledge of the proper optical polarizability of the segment (l - 2) is crucial for the interpretation of data obtained in the study of the spontaneous birefringence in polymer films of PMVA. The films were prepared by free evaporation of the aqueous solutions of different concentrations. The solutions were placed on the horizontal glace plates and evaporation occured at room temperature. The orientational order of anisotropic regions or ‘fragments’ of molecules in the surface layers of PMVA films was evaluated by measuring the birefringence when polarized light passes at different angles to the film surface [3]. The thicknesses of the films were varied in the range of (1-25) m. At high thicknesses the saturation of the birefringence effect is exhibited. The orientational order parameter S of PMVA fragments near the surface was evaluated as S= - (0.16±0.03) by analyzing the birefringence data in solution and in films. The negative sign of S shows that the mean orientation angle to the normal to the film surface for anisotropic PMVA chain fragments is > 54.7°. In other words, anisotropic chain fragments are predominantly parallel with respect to the surface. [1] Pavlov G. M., Okatova O. V., Michailova A. V., Ulyanova N. N., Gavrilova I. I., Panarin E. F. Macromol. Biosci. 2010, 10, 790–797. [2] Polymer Handbook //Ed. By J. Brandrup, E.H. Immergut. N. Y., 1975. [3] Cherkasov, A.N., Vitovskaya, M.G., Bushin, S.V. Vysokomol. soedin., 1976, 18A, 1628–1634.
P-063 A NEW TYPE OF IONOMERS ON THE BASIS OF POLY(PHENYLQUINOXALINE)S
G.G. Nikiforova, N.M. Belomoina, E.G. Bulycheva, M.I. Buzin, M.N. I’lina, V.G. Vasil’ev,
V.S. Papkov A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia
Polyphenylquinoxalines (PPQ) are one of the most promising polyheteroarylenes as materials for various modern technological applications due to their high thermal performance, chemical resistance, excellent solubility in organic solvents and film-forming properties. These polymers are obtained by polycondesation of bis-(o-phenylenediamine) with bis-(-diketones). Sulfonated poly(phenylquinoxaline)s (SPPQ) are a new type of aromatic ionogenic polymers. They were synthesized by the polymer-analogous reaction, i.e., via sulfonation of poly(phenylquinoxaline)s by a mixture of sulfuric acid with oleum. The transformation of PPQ into SPPQ is accompanied by essential changes of its physical and chemical properties, in particular solubility. Thus, in contrast to PPQ, SPPQ containing more than 1.7% of S, is insolubale in chloroform but it can be dissolved in ethanol at the sulfur content above 8%. An increase in viscosity and a polyelectrolyte effect observed in SPPQ in N-methylpyrrolidone solutions should be related to increasing concentration of polar sulfonate groups with increasing sulfonation degree of the pristine polymer. The polyelectrolyte effect can be suppressed by addition of LiCl. According to TGA data, SPPQs contain a significant amount of absorbed water, raising with increasing sulfonate groups content. Introduction of the sulfonate groups in SPPQ leads also to the appearance of a new stage of thermal and thermo-oxidative destruction in a temperature range of 300-4000 C, additional to a high-temperature stage of decomposition near a 5000 C, observed for an initial PPQ. A new class of ionomers was obtained by interaction of SPPQs with hydroxides of alkaline metals ( Li, Na and K).The type of cation was found to influence on aggregation of macromolecules of the synthesized ionomers owing to specific intermolecular interaction of ionic groups that leads to change of solubility and viscosity of solutions of ionomers and deformation and strength characteristics both dry and swelling in water films of the ionomers in comparison with that of initial PPQ and SPPQ. It was shown also that replacement of hydrogen atoms in the sulfonate groups by the alkaline metal ions leads to an increase in the thermal and thermo-oxidative stability of the ionomers in comparison with original SPPQ which become close to those of initial PPQ. This fact is of a special interest in the respect of the development of new thermostable electrically conductive membranes. This work was supported by the Russian Foundation for Basic Researches, project no 14-03-00701
P-064 NON-ISOTHERMAL DESORPTION – THE MEASURING METHOD OF TRANSLATION MOBILITY OF LOW-MOLECULAR-WEIGHT
SUBSTANCES IN POLYMERS*
A.E. Chalykh, T.F. Petrova, R.R. Khasbiullin A.N. Frumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of Sciences
Application of thermo gravimetric device Netzsch TG 209 F1 Iris combined with mass-spectrometer Netzsch QMS 403D Aeolos gives an opportunity to obtain the information on non-isothermal desorption of low-molecular-weight components dissolving in polymers. Based upon the following systems: 1) water – chitosan; 2) water – copolymers of ethylene and vinyl alcohol; 3) water – hydrophilic polymers – glycols was shown that there are weight loss steps in the thermograms and , which appearance can be related with desorption of components, vaporizing within characteristic temperature region. It was shown that combination of mass-spectrometer and TG balance has high enough sensitivity that enables to resolve desorption of low-molecular-weight substances (solvents, plasticizers), which evaporation temperature differs by 5-8 degrees. The diffusion equation of desorption was suggested. It describes a rate of the process, and permits to calculate partial coefficients of diffusion at different temperatures. Comparative studies of water diffusion coefficients in chitosans were carried out by methods of isothermal and non-isothermal desorption. Experimental results are presented in the fig. 1. Comparative data obtained by interval sorption and HMR are presented as well. Simultaneously, partial diffusion coefficients of water, alcohols and glycols were calculated by non-isothermal desorption of multi-component system. It’s important to take into account a variation of composition of multi-component system at successive evaporation of volatile components when analyzing and interpreting experimental data.
Fig. 1. Concentration dependence of diffusion coefficients of water in chitins and chitosans. Literature data: 1 - [1, 2]; 2, 2 – partial diffusion coefficient [3]. Our original data: 3, 4, 5 – by sorption method; 7, 8 – non-isothermal desorption.
[1] - Vasina E.N., Volkov V.I., Sevrugin V.A., Skirda V.D. // in book of papers «Structure and dynamics of molecular systems». Yoshkar-Ola. 1995. Part. 1. p.64. [2] – Volkov V.I., Skirda V.D., Vasina E.N., Korotchkova S. A., Soontarapa K. // Journal of Membrane Science. 1998. V.138. p.221. [3] – Ageev E.P., Voikhoreva G.A., Matyshkina N.N. // Vysokomolec. soed. 2000. А. V.42. №2. p.333. Presented work is supplied by Russian Foundation of Basic Research, Projects No. 14-03-00390
P-065 STRUCTURE OF J-AGGREGATES OF THIAMONOMETHINECYANINE DYES
S.I. Pozin, O.M. Perelygina, V.V. Prochorov, E.I. Mal’tsev
Frumkin Institute of Physical chemistry and Electrochemistry Russian Academy of Sciences, Moscow, Russia [email protected]
In this report we present some results on the study of J-aggregate structures of two thiamonomethinecyanine dyes: CD-1 (left) and CD-2 (right) (Fig. 1). At the present time there is no specific model of molecular arrangement for the aggregates of these dyes.
Fig. 1. Chemical structure of the dyes. These dyes are of interest because of their ability to give well-formed J-aggregates, which are easily observed by fluorescence spectroscopy and AFM-microscopy. The images of J-aggregates were analyzed in this stydy. In aqueous solutions, the CD-1 formed extended J-aggregates of size tens or hundreds of microns with oblique (I) or rectangular (II) end (Fig. 2). Structures with oblique end are monolayers. It was found that the angle of the end is fixed by single value close to 45°. It was proposed a staircase model with a slip angle of 25° for molecular packing for the J-aggregates of type I. The value of the slip angle was obtained from the study of polarized fluorescence microscopy; it was in agreement with simulation data. In the developed model the sides of the aggregates are oriented along the [100] and [110] directions. The angle between them coincides with the experimentally observed oblique angle of 45°. Structures with a rectangular end look like bilayer objects on the AFM-images. However, some optical images of the aggregates in solutions clearly testified that they have tubular structure (Fig. 2). The question of bilayer aggregates formation in solution bulk still remains open. The J-aggregates of CD-2 may differ from CD-1 ones in morphology. Especially it may be true for the monolayer aggregates. However, the dye CD-2 is also able to give extended ribbonlike and rodlike aggregates.
Fig. 2. Optical fluorescent images of CD-1 J-aggregates formed in solution bulk: deposited on the substrate (a), in solution bulk (b).
P-066 ON THE TECHNIQUE OF STRUCTURAL STUDY OF POLYELECTROLYTE COMPLEX
Yu.G. Baklagina1, S.V. Kononova1, V.V. Klechkovskaya2, V.A. Petrova1, E.V. Kruchinina1,
D.P. Romanov3, A.N. Bugrov1, A.S. Orekhov2, L.A. Pyankova4, V.A. Elokhin4 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Peterburg, Russia
2 - Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russia 3 - Grebenshikov Institute of Silicate Chemistry, Russian Academy of Sciences, St. Peterburg, Russia
4 - ZAO Naychnye Pribory, St. Peterburg, Russia [email protected]
Polyelectrolyte complex films (PECs) formed from polymeric counterions based on polysaccharides (chitin , chitosan, cellulose) are of particular interest. Polyelectrolyte pairs of these complexes have a stereoregular structure of similar circuits, relatively high rigidity, a strong intermolecular interactions and the ability to form a strong composite multilayer membranes for liquids separation. In the literature data there are no reports concerning the structural changes occurring with polyelectrolyte components involved in complex formation, as only the physicochemical properties of membranes based on PEC are usually studied and analyzed. At the same time, the transport properties of the membrane depend on the structure of each layer in its composition. The aim of our work was to develop analytical technique that allows to provide essentially new information on the structure, morphology and elemental composition of thin layers of multilayer polymeric membranes and structural changes to their constituents in the course of pervaporative experiments. The offered method of studying the structural characteristics of composite films and membranes based on polyelectrolyte complexes from chitosan and sulphoethyl cellulose (SEC) was designed with using DRON-3M and DIFREI-401 (ZAO Nauchnye Pribory, St.-Petersburg) diffractometers and software package Difract. The device DIFREI-401 is equipped with micrometer adjustment of the horizontal level of a sample that allows to register reflection of a pseudo-sliding X-ray beam from the thin surface layers of membrane. Shooting conditions (fine-focused tube BSV- 33, position-sensitive curved detector, range of simultaneous recording 20o, capillar of 500 microns) allowed to carry out structural analysis of thin polymeric layers of composite films. The study of the modelling membranes obtained by the layer-by-layer deposition of chitosanda=80 and SECds=80 polyions solutions has shown that polymer network nodes were formed during the preparation of the polyelectrolyte complex, and their concentration determines the process of chitosan crystallization [1,2]. In the chitosan layer orthorhombic polymorph modification with crystal cell parameters a = 0,828, b = 0,867, c = 1.042 nm is formed, that corresponds to the structure of the polymorph modification of chitosan formed after the hydrothermal treatment at T=150-200°C and pressure of 150 atm. [3]. The study of morphology and elemental composition of the surface layers and cross-sections of composite films were carried by the scanning electron microscope QUANTA 200 3D and energy dispersive X-ray microanalyzer (EDS). There is a visible interface between chitosan and SEC layers on the images of cross-section cleavages. In the case of the layer-by-layer deposition of polyions chitosanda=80 and SECds=80 solutions, the thickness of the intermediate layer is an order of 500 nm. At the same time, the SEM images of the composite films obtained using SEC with the other degree of substitution indicate changes in the PEC layer. Elemental composition from layer to layer was monitored by EDS spectra. Thus, using the scanning electron microscopy PEC layer has been first visualized, the thickness thereof is defined within the measurement error [2]. Conclusions: The proposed methods allow us to estimate the structure of thin polymer layers of multilayer composite films , visualize PEC layer and determine its thickness. The degree of ordering of one of the components in selected pair is determined both by complementarity of the polymers in PEC, and the degree of realization of PEC contacts. 1.S.V.Kononova, R.V.Kremnev, et al., Crystallography Reports 2011, vol. 56, №3, pp 538. 2.Yu.G.Baklagina, S.V.Kononova, et al., Crystallography Reports 2013, vol.58, №2, pp 268. 3.T.Yui, K.Imada, et al., Macromolecules 1994, vol. 27, pp 7601.
P-067 SILVER-CONTAINING DNA-POLYCATION COMPLEXES
Z. Reveguk1, V. Polshkov1, V. Bakulev1, O. Nazarova2, T. Nekrasova2, Yu. Zolotova2, E. Panarin2, N. Kasyanenko1
1 - Saint-Petersburg State University, Department of Physics, Saint-Petersburg, Russia 2 - Institute of Macromolecular Compounds of Russian Academy of Sciences, Saint-Petersburg, Russia
DNA-polycation complexes are widely used for the fabrication of gene vectors. The formation of these structures is based on self-assembly of swollen DNA and polymeric coils in a diluted solution into discrete nanoparticles. We use silver nanoparticles stabilized by poly(2-(dimethylamino)ethyl methacrylate) (polyDMAEM). AFM method demonstrates that silver nanoparticles are fixed on polymer chain. The plasmonic resonance absorption peak was also observed for polymer solutions. It was shown by the methods of AFM and gel electrophoreses that DNA condensation induced by polycation with silver nanoparticles is realized in 0.005 M NaCl at concentrations corresponding to the ratio of number of polymer and DNA ionic groups N/P>1. At smaller polymer concentration in DNA solution the formation of sophisticated structures was observed with AFM technique. It is known that metallic nanoparticles can produce the significant enhancement of the fluorescence of different agents when they are situated near the fluorophores. DNA as a template can accumulate fluorescent compounds via complex formation in a solution. After the addition of polyDMAEM into DNA-fluorophore solution and its attraction to negatively charged DNA one can expect the interaction of silver nanoparticles with fluorophores. We investigate DNA-DAPI interaction in a solution with the methods of viscosity, circular dichroism, fluorescent spectroscopy and compare the fluorescence of DAPI before and after the addition of poleDMAEMinto solution.
P-068 COMPUTER SIMULATION OF BIORESORBABLE POLYELECTROLYTE COMPLEXES ON THE BASE OF LINEAR AND
BRANCHED PEPTIDES
A.Yu. Khvatov1, V.V. Bezrodniy1, A.A. Mistonova1, I.M. Neelov1,2 1 - ITMO University, St.Petersburg, Russia
2 - Institute of Macromolecular Compounds, St.Petersburg, Russia [email protected]
In recent years new bioresorbable polyelectrolyte complexes on the base of linear and branched peptides were elaborated and used in several biomedical applications. In present study we carried out molecular dynamic simulation of systems consisting of oppositely charged linear polyelectrolytes (on the base of polylysine and polyglutamine acid or polylysine and polyasparagine acid) or linear and branched peptide polyelectrolytes using AMBER forcefields. Molecular dynamics simulation of linear and branched polyelectrolytes and their complexes was performed using simulation package GROMACS. A model with full atomic details and force field Amber99-SB-ildn were used. Systems consisting of two oppositely charged linear polyelectrolyte molecules or lysine dendrimer and oppositely charged linear polyelectrolyte in cubic simulation cell filled with water molecules and counterions were studied. Counter ions (Na+ and Cl-) were added to ensure electroneutrality of the system. In this study, we calculated structural characteristics of complexes, in particular, the radii of gyration, anisotropy of shape and distribution functions. The results were compared with corresponding characteristics of single polyelectrolytes which constitute the complex. For complexes of linear polyelectrolytes and oppositely charged dendrimers the results were compared with theoretical predictions of complexes of polyelectrolyte chains and spherical polyions. This work was partially supported by RFBR grants 13-03-00524 and Government of Russian Federation grant 074-U01. Computing resources and software packages have been provided by Moscow State University (“Lomonosov” and “Chebyshev” supercomputers).
P-069 ELECTROPOLYMERIZATION OF BIS(4-CYANO-1-PYRIDINO) ALKANES. ELECTROCHEMICAL AND SPECTROSCOPIC STUDIES OF
THE RESULTING POLYVIOLOGEN FILMS
M.N. Zhidkova1, K.E. Aysina1, V.K. Laurinavichyute2, V.Yu. Kotov1 1 - Institute of Natural Sciences, Moscow City Teacher Training University, Moscow 105568, Russia
2 - Department of Chemistry, Moscow State University, Moscow 119991, Russia [email protected]
The ten bis(4-cyano-1-pyridino) derivatives with alkyl chains (n=2-6) and different anions (Br-, HFe(CN)6
3- and Fe(CN)63-) have been synthesized and characterized by 1H-NMR, single-crystal X-
ray analysis and UV-VIS spectra. The electropolymerization of the obtained monomers was performed under the potentiostatic conditions according to the following scheme:
+2ē, -2CN-
The current efficiency of electrodeposition increased dramatically with increasing alkyl chain length, indicating the crucial role of oligomer flexibility. Varying the counter anion in the polymerization solution also affected the polymerization rate, namely, Fe(CN)6
4- anion promoted 1.5-3 fold higher polymerization rate than do Br- or Fe(CN)6
3-. The latter effect can be ascribed to the better polymer stability due to stronger association of polymer with Fe(CN)6
4- anions. To verify this hypothesis we have studied the effects of the counter anion of supporting electrolyte and the solvent on the redox behavior of the resulting polymer films. The kinetic of charge transport in the film bulk is also discussed. A Cottrell equation was applied to analyze kinetic data obtained from double-step chronoamperometry experiments. The resulting apparent diffusion coefficients decreased with the anion size and increased with alkyl chain length. Finally, the electrochromic behavior of obtained polymers is found to be dependent on the alkyl spacer length and nature of doping anion.
P-070 CHEMOSELECTIVE SYNTHESIS OF O-(2-SULFOETHYL)CHITOSAN AND ITS AGGREGATION BEHAVIOR
D.D. Chernyakov1, V.A. Petrova2, E.R. Gasilova2, Y.G. Baklagina2, Y.A. Skorik2
1 - St.Petersburg State Chemical Pharmaceutical Academy, Analytical Chemistry Department, St.Petersburg, Russian Federation
2 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, St.Petersburg, Russian Federation [email protected]
Chitin and its deacetylated derivative chitosan possess a series of unique physical, chemical and biological properties. Unfortunately, the insolubility of chitin in water solutions and the limited solubility of chitosan in solutions having pH below 6 poses certain obstacles for broad practical application of these polymers. For this reason, much effort has been applied to the development of suitable procedures for preparation of water-soluble derivatives of chitin and chitosan that would be feasible for use in a broad scale of applications from plant protection to human medicine. In the present study, an investigation of chitosan sulfoethylation in heterogeneous conditions by applying sodium 2-chloroethanesulfonate (85% isopropanol, NaOH, 80C, different chitosan preactivation procedures) is described, and the influence of the byprocesses both promoting and hampering the formation of the final product is investigated. The obtained chitosan derivatives were characterized using 1H NMR spectroscopy and elemental analysis in terms of the degree of sulfoethylation and the substitution selectivity. It has been shown that sulfoethylation of chitosan under the reaction conditions used proceeds exclusively at the hydroxyl group of chitosan resulted in the formation of O-(2-sulfoethyl)chitosan (SEC). The ratio of the products of the alkylation, hydrolysis, and dehydrohalogenation reactions that concurrently take place in the reaction mixture was determined using 1H NMR spectroscopy of the supernatant solutions and of the SEC. By dynamic light scattering it was shown that aggregation takes place in aqueous solutions of SEC. It was found that dilute aqueous solutions of SEC in 2% NаОН contain species of two different sizes with modes at 20±10 nm (single macromolecules, unimers) and 262±5 nm (intermolecular aggregates). In acidic and neutral media, an unstable formation/dissociation of the aggregates was observed. In static light scattering a structure-sensitive ratio Rg/Rh is equal to 0.24, which indicates the irregular density distribution in the aggregates with a maximum density at the center of the aggregates. The introduction of sulfoethyl group resulted in the solubility of SEC in acidic and alkaline solutions. However, the interaction of cationic (-NH3
+) an anionic (-SO3-) functional groups of the
SEC leading the formation of inter- and intramolecular ionic crosslinking can be used as a way to control the solubility of the films and fibers. XRD analysis shows the increase in amorphization of SEC films with increasing of the degree of substitution. The loss of solubility of the films during 10-months storage is most probably caused by the formation of ionic crosslinking and dehydration, which is confirmed by the presence of 2 peak at 16.5 indicated a change in the intermolecular package. The kinetics of swelling of the SEC films in the Na-form showed the influence of the degree of sulfoethylation on the solubility of the films and the degree of swelling in saline. Acknowledgment: Daniil Chernyakov is grateful to the Foundation for Assistance to Small Innovative Enterprises for the financial support.
P-071 INTERACTION OF CATIONIC MONOMER WITH SODIUM DODECYL SULFATE IN A CONCENTRATED AQUEOUS SOLUTION: EPR
STUDY
E.G. Dukhanina1, M.V. Motyakin2, Yu.A. Zakharova3, Yu.V. Shulevich1, A.M. Vasserman2, A.V. Navrotskii1, I.A. Novakov1
1 - Volgograd State Technical University, Chemical engineering, Volgograd, Russia 2 - Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow , Russia
3 - Moscow State University, Department of Polymer Chemistry, Moscow, Russia [email protected]
Template polymerization on surfactant’s micelles is a promising method for polymers synthesis, which allows to use all the advantages of the template synthesis, and to avoid its main drawbacks. For this method it is important to study the mechanism of interaction between the monomer and surfactant. In a previous study the effect of a cationic monomer (trimethyl[methacryloxyethyl]ammonium methyl sulfate) on the formation, structure, and local dynamics of associates resulted from the interaction of the monomer with sodium dodecyl sulfate (SDS) in dilute aqueous solutions (SDS concentration is 15 mM) was studied by ESR spectroscopy [1]. It has been found that in the presence of the monomer, micelles are formed at concentrations much lower than the CMC of the pure surfactant and the monomer molecules form a condensed layer of counterions around a micelle of SDS. However, it should be noted that the polymerization is usually carried out at a high concentration of the monomer (about 1-2 mol/l), which is considerably higher than the one was studied. Obviously, the increase in the monomer concentration will lead to an increase in surfactant concentration. It’s difficult to predict how the increase in ionic strength of the reaction mixture will affect on the interaction of the monomer with SDS micelles. In this study four fixed SDS concentrations (70, 150, 250 and 500 mmol/l) were investigated. Hydrophobic probe 5-doxylstearic acid (5DSA) as well as hydrophilic cationic probe N,N-dimethyl-N-(4-tempoyl) ammonium iodine (CAT1) were used as spin probes. Independently on the SDS concentration, addition of monomer causes an increase in 5-DSA rotation correlation time and a decrease in constants of hyperfine interaction (HFI), which have sharp behavior up to [M]/[SDS]≈1. It confirms that monomer effectively binds with SDS micelles in the entire investigated range of SDS concentrations and ratios [M]/[SDS]. Anisotropic nature of the CAT1 rotation indicates its localization in the near-surface layer of the micelle. Monomer binds with micelles at minimal ratio of the mixture (up to [M]/[SDS]≈0.2) and it cause an increase in rotational correlation time and a decrease in HFI constants. It can be assumed that when the monomer concentration in the mixtures is much less than the SDS concentration, monomer ions only limit the mobility of the nearby probe and reduce the local dielectric constant due to the displacement of water molecules. Further growth of the monomer concentration causes an increase in HFI constants and a decrease in rotation correlation time, it suggests the displacement of the probe into solution. These results clearly indicate that the maximum concentrations of the components and quite high ionic strength of the solution did not suppress the binding of SDS micelles with the monomer and template polymerization of the monomer in the presence of micellar surfactants can be implemented. The study was supported by Russian Foundation of Fundamental Researches (grant 13-03-00822). 1. Motyakin, M.V. Interaction of Cationic Monomer with Sodium Dodecyl Sulfate in Dilute Aqueous Solutions: ESR Study / M.V. Motyakin [et al.] // Colloid Journal. – 2009. – V.71, № 5. – P. 672-676.
P-072 MICELLE FORMATION OF AMPHIPHILIC BLOCK COPOLYMERS BASED ON N-VINYLPYRROLIDONE IN LANGMUIR
MONOLAYERS AND LANGMUIR-BLODGETT FILMS
O.G. Zamyshlyayeva1, O.S. Lapteva1, M.A. Batenkin2, Yu.A. Bykova1, N.B. Melnikova3 1 - N.I. Lobachevsky Nizhniy Novgorod State University, Nizhniy Novgorod, Russia
2 - G.A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Nizhniy Novgorod, Russia 3 - Nizhny Novgorod State Medical Academy, Nizhniy Novgorod, Russia
The physic-chemical characteristics of the monolayers formation of amphiphilic block copolymers of poly(N-vinylpyrrolidone-block-2,2,3,3-tetrafluoropropylmethacrylate) (PVP-b-PFMA) containing 10 wt.% of PVP (Mw of hydrophilic block was from 22000 to 57000) and poly(N-vinylpyrrolidone-block-styrene) (PVP-b-PS) at the water-air interface and on solid (quartz, silicon) have been studied. It has been shown by using UV-, IR-spectroscopy, isotherm compression π-A-methods and AFM imaging that the state of PVP-b-PFMA monolayers on aqueous subphase and solid supports was varied with Mw(PFMA)-Mw(PVP) ratio, the aggregation of copolymers as well in solution as the surface layers (surface micellation and phase isolation). Gibb´s surface energy of the films transferred in solid substrates was increased up 30-33 mJ·m-2 from 21 mJ·m-2 (poly-2,2,3,3- tetrafluoropropylmethacrylate). As well the adhesion work Wa (monolayer-water droplet-air) and Wa(monolayer-octanol droplet-water medium) as AFM imaging characterize lipophility and surface topology suitable for thromboresistant materials. We have studied the block copolymers of PVP-b-PS with high proportion of the hydrophilic block (65-71 wt.%) and the content of PVP block 5-7 wt.%. It was obtained sufficiently high pressure (π = 40mN/m) for block copolymer PVP-b-PS containing a small fraction of the hydrophilic block indicates the formation of stable monolayer, which is formed by the perpendicular orientation of the macromolecules of the interface: the hydrophilic groups are immersed in water, and remain on the surface hydrophobic and line. There is destruction of the monolayer at 3.5-4 mN/m for the block copolymers, containing 66 wt.% PVP, which characterized significantly lower values . This is due to the process of micelle formation, accompanied by dipping macromolecular associates in the bulk phase due to high content of hydrophilic block. In monomolecular films on solid substrates for PS-b-PVP (65-71%) also recorded AFM micellar structures.
P-073 PREPARATION AND INVESTIGATION OF VASCULAR IMPLANTS BASED ON ALIPHATIC COPOLYAMIDE
P.V. Popryadukhin1, I.O. Lebedeva1, G.I. Popov2, G.U. Yukina2, E.M. Ivankova1,
I.P. Dobrovolskaya1, V.E. Yudin1 1 - Institute of Macromolecular Compounds RAS, Saint Petersburg, Russia
2 - Pavlov First Saint Petersburg State Medical University, Saint Petersburg, Russia [email protected]
Actual problem of modern science of materials is development of materials of medical appointment, which can be using, for example, in transplantology. The materials must have some properties: biocompability, predicted bioresorbtion, non-toxicity of materials and products of their decomposition and structure, providing good adhesion of stem and somatic cells, their effective proliferation. Products from materials having these properties can be used as implants of organs, in particular, blood vessels. As a material of implants used the nanofibres from copolymer ε-caprolactam and adipic acid salts (CoPA). The film and tubular samples on the basis of nanofibres from CoPA which were used as implants of vessels were obtained by the method of electrospinning of nanofibres.
The obtained samples (Fig. 1) were investigated by a method of electronic scanning microscopy. Film and tubular samples consist of fibers with diameter 300-700 nm (Fig. 2). It is revealed that thickness and structure of walls is defined by the speed of supply of solution and formation time, and also speed of rotation of an electrode. Studying of mechanical and barrier properties of implants was one of the important ways of work. It was shown that mechanical and barrier properties of tubular samples allow them using as implants of blood vessels. Tests in vivo of the obtained tubular samples were
carried out. The researches as abdominal aorta of a rat showed: there is no formation of blood clot in place of contact of native and artificial vessel. For 3-7 days on an internal surface of an implant is formed the layer of endotelial cells, and also subendotelial layer. During supervision over activity of animals isn't revealed negative influence of implants on a condition of animals. As a result:
1. It was obtained the tubular samples on the basis of nanofibres from CoPA.
2. Mechanical and barrier properties of tubular samples allow them using as implants of blood vessels.
3. The researches in vivo as abdominal aorta of a rat showed:
There is no formation of blood clot On internal surface of an implant is formed the layer of endotelial cells, and also
subendotelial layer Supervision over animals didn't reveal negative influence of an implant on their condition.
Fig.1 Tubular samples
Fig.2 Structure of nanofibers
P-074 NOVEL POLYAMIDE 12/CR2O3 NANOCOMPOSITES. COMPLEX CRYSTALYZATION KINETICS
E.S. Shapoval1, V.V. Zuev2
1 - National Research University of Information Technologies, Mechanics and Optic 2 - Petru Poni Institute of Macromolecular Chemistry
The reinforcement of polymers with nano-scaled fillers developed a new class of advanced multifunctional materials with improved properties, used in many fields raged from microelectronics to aerospace. The nanoparticle selection depends on the target properties of polymer composites (thermal, magnetic, optoelectronic etc). Due to its good magnetic and electric properties chromium oxide (Cr2O3) is one of the preferred and best characterized filler materials, which is combined with polymers, i.e., to record media and in medical applications. Our choice of polyamide-12 (PA12) as polymer matrix is due to its low temperature adhesiveness, its ability to disperse pigments and its miscibility with many commercial polymers. The PA12 based polymer nanocomposites were obtained by polymerization of fine mechanically mixture of lauryl lactam (Aldrich) with calculated amount of Cr2O3 powder. The polymer nanocomposites with different Cr2O3 loading (0.1-10 wt.%) have been prepared. The Young’s modulus and the tensile strength elongation of the nanocomposites increased sleight at low filler loading. Furthermore, both these parameters decreased significant with increase in filler concentration. This mainly attributed to the carbon particles aggregating easily as the filler concentration increase. We studied the influence of such nanoparticles on the isothermal crystallization kinetics and melting behaviour of PA12 in order to design nanocomposites with adequate control over desired properties. The time to reach 10% transformation (τ0.1) of PA12, calculated from the partial areas of each exothermic curve show three facts that must be considered. Firstly, the τ0.1 of PA12 nanocomposites increased exponentially with temperature, confirming that the ordering process occurred through a nucleation mechanism. Secondly, the crystallization interval of PA12 shifts to higher temperature with the addition of Cr2O3 nanoparticles. Finally, the crystallization rate of PA12 in nanocomposites which can be considered as 1/ τ0.1, increased strongly in nanocomposites with 0.1-1 wt% of Cr2O3 nanoparticles suggesting that the well dispersed nanoparticles have a remarkable contribution to enhance the nucleation of PA12. The opposite effect observed for composites with agglomerated nanoparticles (5-10 wt% of Cr2O3). The Avrami approximation can properly describe the isothermal crystallization the investigated nanocomposites. Acknowledgements: This work was partially financially supported by Government of Russian Federation, Grant 074-U01.
P-075 MOLECULAR ORDER OF SUPRAMOLECULAR POLYANILINE NANOSTRUCTURES
N.N. Saprykina1, A.K. Tihomirov1, I.Yu. Sapurina1, M.A. Shishov2, P.G. Travkin3, V.A. Starcev3
1 - Institute of Macromolecular Compounds Russian Academy of Science, Saint Petersburg, Russia 2 - Institute of Macromolecular Compounds Russian Academy of Science, Saint Petersburg Electrotechnical University
‘‘LETI’’, Saint Petersburg, Russia 3 - Saint Petersburg Electrotechnical University ‘‘LETI’’, Saint Petersburg, Russia
Conjugated polyaniline (PANI) is an organic semiconductor, and successfully used in different electronic devices: sensors, energy storage and photovoltaic elements. Polymer properties and efficiency of its use mainly define by polyanilinesupramolecular organization. At the same time PANI could be prepared in many different supramolecular structures: 3D spherical particles, 2D tapes and boards, 1D – nanowires, sticks and tubes (fig.1), and hierarchical formations based on those structures. In present work characteristics of all types of PANI structures we received by wide angle X-ray analysis. Interconnection between supramolecular polymer organization and molecular order up to the tenths of nanometers was shown. X-ray patterns of conducting PANI with 3D structure consist of two wide peaks 2θ = 20о 4.4A (periodicity along polymer chains) and 2θ = 25о3.5A (periodicity across polymer chains) which intensity is comparable. For 1D structure of nanowires and nanotubes increase of 2θ = 25оpeak is characteristically, which corresponds with more regularly chain lay down. 2D structures have the most crystallinity and have additional sharp peak in range of 2θ = 6 -7о. High level of far order with sharp 2θ = 2.5о peak specific for 30 A regularity, detected in colloidal PANI particles, stabilized by organic doping acid. Diffractograms show layered structure where PANI chains orient parallel to each other and divided by 30 A intervals, corresponded with doping acid molecule size. Obtained results can be discussed from the point of view aniline oligomer structures, polymer chains structure and its lay down.
P-076 INTERACTIONS OF DNA WITH BIOMIMETIC SYSTEMS: INSIGHT FROM MOLECULAR DYNAMICS SIMULATIONS
A.Yu. Antipina1, A.A. Gurtovenko2
1 - Department of Physics, St. Petersburg State University, Petrodvorets, St. Petersburg, Russia 2 - Department of Physics, St. Petersburg State University, Petrodvorets, St. Petersburg, Russia; Institute of
Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia [email protected]
Interactions of DNA molecules with biomimetic systems such as biomembranes play an important role in many biologically relevant processes and in bionanotechnology. The numerous examples include interactions of nucleic acids with lipid molecules in cell nuclei, formation of the nuclear pore, and liposome-based gene delivery vectors. Despite the importance of the DNA-biomembrane interactions the molecular mechanisms behind such interactions and the microscopic structure of corresponding supramolecular complexes remain largely unknown mostly due to limitations of existing experimental techniques. To address this problem, in this work we employ atomic-scale molecular dynamics simulations to gain a better understanding of the structure and properties of supramolecular complexes of DNA with phospholipid bilayer membranes. Such membranes are often considered as biomimetic models of plasma membranes of living cells. Several structural characteristics of the "DNA-membrane" system will be studied, with a special focus on the changes in the structure of both the membrane and DNA upon complexation. Overall, the use of computational models of high (atomistic) resolution will allow us to get unprecedented insight into the interactions of DNA with phospholipid membranes. This work was supported by the Russian Foundation of Basic Research (Project 14-03-01073-a).
P-077 MOLECULAR MOBILITY IN AQUEOUS SOLUTIONS AND GELS OF POLYDIPHENYLENESULFOPHTHALIDE
L.A. Wasserman1, I.I. Barashkova2, V.G. Vasil’ev3, V.S. Papkov3, A.M. Wasserman2
1 - Institute of Biochemical Physics RAS 2 - Institute of Chemical Physics RAS
3 - Institute of Organoelement Compounds RAS [email protected]
Polydiphenylenesulfophthalide consists of an aromatic backbone and side cyclic sulfophthalide groups. While the rigidity of the main chain is enhanced by hydrophobic biphenylene groups in рolydiphenylenesulfophthalide, the specific chemical and physical characteristics are provided by triphenylmethane fragments and polar ionogenic sulfo groups in sulfophthalide rings. The polymer is characterized by high glass transition temperature (300°C). However, despite its aromatic origin and the enhanced rigidity of macromolecules, the presence of side cyclic sulfophthalide groups makes рolydiphenylenesulfophthalide soluble in a number of solvents, thereby opening an opportunity for its processing from solution. The dimensions of associates in aqueous solutions of polydiphenylenesulfophthalide and products of its treatment with alkalimetal hydroxides are measured by light scattering technique. According to EPR spin probe spectroscopy, the associates are hydrophobic structures. The hydrophobic core is heterogeneous. Nevertheless, it may contain a certain amount of “defect” (less ordered) regions. The structure of hydrophilic corona affects on the molecular mobility of hydrophobic core. The local mobility of polydiphenylenesulfophthalide associates is lower than that of associates of the polymer treated with alkalimetal hydroxides, however, in both cases this value is commensurable with the local mobility of the solid polystyrene. The molecular mobility of polydiphenylenesulfophthalide associates in gels is approximately in 2-3 times less than in solution. The heterogeneous structure of associates is formed in diluted solution and remains invariable in gels.
P-078 POLY(METHYLPHENYLSILANE) DOPED WITH FULLERENE C60 AS A BASIC COMPONENT OF THIN FILM SOLAR CELLS
S.V. Kostromin1, V.V. Zuev1, N.V. Kamanina2, S.V. Bronnikov1
1 - Russian Academy of Science, Institute of Macromolecular Compounds, St. Petersburg, Russian Federation 2 - Vavilov State Optical Institute, St. Petersburg, Russian Federation
Polysilanes are known to be a type of σ-conjugated polymers. They exhibit photoconductivity with large hole mobility, broad photoluminescence and transparency in the visible region. Being doped with fullerene, they form intermolecular charge transfer complexes and exhibit photoinduced electric conductivity [1]. Based on this phenomenon, fullerene-doped polysilanes seem to be a promising material for thin film solar cells. These cells have been produced and their photovoltaic characteristics have been investigated [2, 3]. As compared with traditional silicon solar cells, polysilane solar cells have easier production process, lower cost, light-weight and flexible substrates. We synthesized poly(methylphenylsilane) (PMPS) and prepared PMPS samples doped with fullerene C60 by dissolving both components in o-xylene. We investigated C60-doped PMPS both in solution and as films. The latter were obtained by pouring the PMPS solutions onto a glass substrate. The C60 content in PMPS varied from 0.07 to 1.92 wt%. On the absorption spectra of pure PMPS in UV-vis region a wide characteristic band in the region of 300-400 nm could be recognized. In the spectrum of the C60-doped polymer (1.85%), it spreads to larger wavelengths and its maximum shifts from 345 to 380 nm. This shift can be attributed as a batochromic shift; it indicates formation of intermolecular charge transfer complex between a polymer and a dopant. Besides, in the spectrum of the doped polymer, a wide absorption region (440-670 nm) related to interaction between the polymer and fullerene appears. C60 concentration equal to 0.8 wt% was found to be a critical concentration. Exceeding this concentration guarantees PMPS/C60 complex formation. Using thermal gravimetric analysis, we found increasing thermal stability of PMPS when doped with C60. This proves complexation between PMPS and C60. We also investigated the effect of optical limiting of the C60-doped PMPS films using a nanosecond pulsed Nd-YAG laser (second harmonic, λ = 532 nm). For the PMPS sample doped with low C60 content (0.40 wt%), the output laser irradiation energy is proportional to its input energy. However, for the PMPS films doped with C60 (concentrations 1.11 and 1.85 wt%), the absorbance saturation occurs at about 6 mJ. Yet, above 6 mJ, the output laser energy increases again, probably because of samples heating and consequent change in the refractive parameters of the samples tested. Financial support of the Russian Foundation of Basic Research (Project No 13-03-00033) is gratefully acknowledged. References
1. Acharya A., Seki S., Saeki A., Tagawa S. 2006 Synth. Met. 156 293 2. Mizuno T., Akasaka Y., Tachibana H. 2012 Jpn. J. Appl. Phys. 51 10NE31 3. Oku T., Nakagawa J., Iwase M., Kawashima A., Yoshida K., Suzuki A., Akiyama T.,
Tokumitsu K., Yamada M., Nakamura M. 2013 Jpn. J. Appl. Phys. 52 04CR07
P-079 LUMINOPHORE-CONTAINING MONODISPERSE POLYMERIC PARTICLES: DESIGN AND SELF-ASSEMBLING
N. Shevchenko1, E. Tomsik2, G. Pankova1, B. Shabsels1, A. Yakimansky1, A. Koshkin3, A. Sel’kin4
1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, St. Petersburg, Russia 2 - Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
3 - Center of Photochemistry of Russian Academy of Sciences, Moscow, Russia 4 - Ioffe Physical-Technical Institute of Russian Academy of Sciences, St. Petersburg, Russia
Modern polymer science has developed many methods to prepare monodisperse polymeric particles. In particular, heterophase polymerization technique allows preparing uniform particles from 30 nm up to 10 μm in diameter. These particles are of great interest for nanotechnology, since their self-assembling from dispersions is a promising way to design of novel materials with hierarchic structures. For instance, 3D-ordered arrays of submicron particles demonstrate photonic band gap (PBG) in the spectral range of visible or near IR light, which are of importance for optoelectronics. Moreover, in the ordered arrays built up by dye-containing uniform particles, absorption or emission spectra remarkably changes in the PBG vicinity, which can be also used in various applications. The dye-containing particles can also serve as sensing elements, since dyes in their surface layers ensure optical response to various analytes in contacting liquid or gas phases due to their complexation with the dyes. Hence, there is a drive to develop new methods for surface modification of monodisperse polymeric particles with dyes forming sensing sites. At first, monodisperse polymeric particles were synthesized by heterophase copolymerization of styrene and methacrylic acid and ion-exchange of cationic chromophores (Rhodamine 6G, Nile Red) on the negatively charged particle surface was carried out. Besides, poly(styrene-co-N-vinylformamide) particles were prepared using 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIP) as a radical initiator. The surface of these particles was both hydrophilic and amphiphilic due to the acidic hydrolysis of terminal AIP units, forming carboxylic groups and the hydrolysis of N-vinylformamide units, forming aliphatic amino groups, which were used for Fluorescein isothiocyanate covalent binding. Alternatively, core-shell monodisperse particles were prepared by seeded dispersion copolymerization of styrene. Dye-containing comonomers were added at the last copolymerization step and incorporated into particle shells along with cross-linkers. To enhance the selectivity of the interaction between dyes and analytes, molecular imprinting technique was applied. For this purpose, seeds obtained at the first copolymerization step were washed and swollen with cross-linkers, dye-containing comonomers and molecular templates (methanol, ethanol). This approach allowed generating robust and highly selective synthetic receptors for such small molecules in the particle surface layer. Effects of the methods of dye incorporation on fluorescence spectra of particle arrays and their changes in the presence of volatile analytes were revealed. Obtained results showed a good promise of arrays built up with dye-containing polymeric particles as sensing elements. This work was supported by the Russian Foundation for Basic Research (project no. 13-03-00741-a) and the Program of the President of the Russian Federation for the Support of Young Scientists (grant no.SP-968.2012.5).
P-080 TRIBOLOGIC BEHAVIOR OF POLYIMIDE-BASED NANOCOMPOSITE MATERIALS CONTAINING DIFFERENT TYPES OF
NANOPARTICLES
I. Gofman1, I. Abalov1, O. Orell2, J. Vuorinen2, A. Bugrov1, V. Yudin1 1 - Institute of Macromolecular compounds RAS, St.-Petersburg, Russia
2 - Tampere University of Technology, Tampere, Finland [email protected]
The friction processes were studied in the friction couples “polymer-based nanocomposite/steel” in a wide range of temperatures: from RT to 200 oC. The nanocomposite materials to be tested were formed basing on a commercially available thermoplastic polyimide Ultem-1000 (Sabic Co). The following types of nanoparticles were used as active filers: carbon nanofibers (VGCF), carbon nanocones/discs (CNC), natural halloysite nanotubes, and zirconium dioxide doper with yttrium oxide. The nanoparticles of ZrO2-Y2O3 were used in the concentration of 1.8 vol.%, and all other nanofillers were introduced in the matrix polymer in the concentrations of 3 vol. %. The friction tests were performed using the CETR UMT-2 tribometer (CETR Corporation, USA). The steel counterbody’s run during the tests was about 3 500 m. Both the friction coefficient k values and the specific wear rate W were determined during these tests. W were determined as follows: W = m/(LFz), where m denotes the mass loss during the test, L is the running distance during the test, – the density of polymer tested, and Fz – the normal contact load. The increase of the test temperature yields in different types of behavior of the k values at the beginning of the friction test (k1) and at steady-state region of the friction process, after ~ 1000 m of run (k2). The first of these two values increases monotonously in all range of the temperatures from ~0.4 at RT to ~ 0.5 at 200 oC for both Ultem sample and all composites tested. Meantime the k2 values of the nanocomposites containing CNC, halloysite, and ZrO2-Y2O3 tend to a dramatic decrease up to 0.15-0.10 in the range of 150-200 oC. This process reflects the formation of the micro-layer of polymer melt at the friction surface. The very low wear rate values (less than ~ 510-4 mg/(Nm)) were registered in the friction tests carried out with both the Ultem and the nanocomposite samples. The pronounced effect of the W decrease was registered in the tests at 200 oC for the nanocomposites containing both halloysite nanotubes and ZrO2-Y2O3. For the latter the minimal W value at 200 oC was registered as low as 5.610-5 mg/(Nm). Acknowledgements The financial support provided by Russian Foundation for Basic Research (project No. 13- 03- 00547) is acknowledged.
P-081 BIORESORBABLE VASCULAR PROSTHESES FROM POLYLACTIDE
P.V. Popryadukhin, G.I. Popov, V.E. Yudin, G.Yu. Yukina, I.P. Dobrovolskaya
Institute of Macromolecular Compounds RAS, Sain-Petersburg, Russia [email protected]
Cardiovascular diseases are the leading cause of death and disability worldwide. One of the most significant types of treatment patients with diseases of cardiovascular system is surgical operations, during which it is necessary to replace or bypass the affected vessels. Currently, surgeons use autologous arteries, veins, homo- and xenografts, synthetic prostheses. But they do not meet fully the requirements of modern cardiovascular surgery, especially if it is necessary to reconstruct the vessel with diameter 4-6 mm and less. One of approach to obtain the tissue engineered vascular graft (TEVG) is a technology in which is used the biodegradable polymer matrix. First step is obtaining a polymeric scaffold with specific mechanical, physical and chemical properties. After implantation such prosthesis, cells of the recipient organism proliferate and differentiate in its wall forming the new vessel. In parallel, there is a process of biodegradation scaffold's polymer. Gradually polymer degradation completes and occurs integration between "vessel" and the surrounding tissues of the recipient organism. Use of bioresorbable polymer scaffolds is the basis of this method. Eventually, the scaffold is replaced with the extracellular matrix, which is synthesized by the cells, thus forming a new vessel. We have developed bioresorbable polymer scaffolds based on nonwoven nano- and microfibers obtained by electrospinning of a biocompatible polymer polylactide (Figure 1). During microvascular surgery, polymer scaffolds were implanted into the abdominal aorta of rats. Then, after a certain periods, the grafts were explanted from the animals and examined (histology and electron microscopy). It was shown, that after 1 month occurs sprouting through the polymer scaffold the recipient tissue and on the inner surface there is a continuous layer of endothelial cells. After 3 months, revealed signs of bioresorption polymer fibers and their replacement by tissues of the recipient. In the future, it is necessary to increase the observation period to assess dynamics of the polymer matrix resorption.
Fig. 1. Polymer scaffolds based on nanofibers obtained by electrospinning of polylactide, surface (a), cross-section (b).
P-082 SYNTHESIS OF WATER-SOLUBLE POLYMERIC CHELATING AGENTS USING HYDRAZONE LIGATION TECHNIQUE
K.V. Polyanichko, M.V. Leko, E.F. Panarin, I.I. Gavrilova, A.V. Dobrodumov, S.V. Burov
Institute of Macromolecular Compounds of Russian Academy of Sciences , St Petersburg, Russia [email protected]
Synthetic polymers are widely applied as a vehicle for targeting antitumor compounds and diagnostic agents to cancer cells. Due to well-known EPR effect, macromolecules can gradually accumulate in tumour tissue. It permits considerably increase the local concentration of attached cargo molecules. An application of polymeric carriers seems to be especially promising in the field of so-called theranostics – the cutting-edge area integrating diagnostic and therapeutic approaches to ensure the most efficient treatment of oncological diseases. Here we describe synthesis of polymeric chelating agents by the modification of functionalized water-soluble carrier using hydrazone ligation technique. As promising variant of carrier molecule soluble both in water and organic solvents we have chosen copolymer of N-vinylpyrrolidone and acrolein diethyl acetal (MW 50 000 Da). Removal of acetal protection by 0.1 N HCl resulted in formation of reactive aldehyde groups (7 molar percent as determined by 1H NMR spectroscopy). 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) derivatives are widely applied for cancer detection using PET, MRI and luminescent imaging methods. Thus, synthesis of polymeric carriers containing predetermined amount of DOTA moieties is of particular interest for early diagnostics of oncological diseases. The modification of PVP-acrolein (PVP-AC) copolymer using hydrazone ligation approach implies application of building blocks containing hydrazide functional group. For this end we synthesized different branched structures containing 4 copies of DOTA using SPPS technique and special type of polymer resin for hydrazide synthesis. The deprotection of final product and its cleavage from polymer support was achieved using 95% TFA : 2.5 % H2O : 2.5% TIS mixture. It permits to ensure complete removal of protecting groups and minimize the side reaction of hydrazide trifluoroacetylation. The conjugation of synthesized derivatives with PVP-AC copolymer proceeds smoothly in acetate buffer (pH 5) and subsequent reduction of hydrazone bond by NaBH4 leads to desired polymeric chelating agent. The number of attached DOTA groups can be quantified by amino acid analysis and 1H NMR. In the last case direct investigation of polymeric carrier is complicated by the overlapping of DOTA signals with that of polymer backbone. The structure of synthesized carrier and its ability to form stable complexes with metal ions was confirmed in experiments with EuCl3. The complexation of Eu3+ ions by heating of polymer solution in DMSO up to 60 0C results in characteristic shift of DOTA signal in NMR spectrum. These results suggest that hydrazone ligation technique is a promising method for the fast and efficient design of polymeric chelating agents potentially useful in different types of diagnostic systems.
P-083 MONTE CARLO SIMULATIONS OF NATURAL UNSATURATED HYDROCARBON OLIGOMER CHAINS
D.V. Zhurkin1, A.L. Rabinovich2
1 - Petrozavodsk State University, Petrozavodsk, Russia 2 - Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, Petrozavodsk, Russia
Unsaturated hydrocarbon chains are examples of the most important natural molecules; they play the key role in various processes of biological membranes as constituents of phospholipid molecules. Computer simulations of various lipid membrane systems and their constituents allow to elucidate at the molecular level the detailed relations between the chemical structure and physical properties of various molecules. This work presents results of Monte Carlo simulations of ~70 unperturbed linear hydrocarbon chains CH3-(CH2)a-(CH=CH-CH2)d-(CH2)b- CH3 with N carbons and d methylene-interrupted cis double bonds (N = 16, 18, 20, 22; d = 0, 1, 2,…, 6). Conformational energy of a linear hydrocarbon chain was represented as sum of energies Um(, , 2) of several structural units, where , , 2 are torsion angles, i.e., a scheme of interdependence of each three torsions along the chain was used. The units reproduced precisely the structure of various chain fragments. The energies Um were calculated using CHARMM27 force field. To calculate average characteristics, importance sampling technique was developed for the efficient generation of chain conformations, with continuous variation of all single C-C bond torsions within (0, 360) range considered; 129 600 000 000 – 1 296 000 000 000 conformations of each chain were generated at T=293, 303, 313 K. Mean square radius of gyration <S2>, end-to-end distance <h> of each chain and some characteristics in the principal-axes coordinate system such as spans <g1>, <g2>, <g3> in three orthogonal directions were calculated; the span gi of a chain in i-direction is defined as the shortest distance between a pair of planes perpendicular to i-direction such that the chain is contained entirely between them (the axis 1 denotes the shortest dimension, 3 - the longest one). Shape of a chain conformation can be characterized by 3 spans (mean dimensions of the “minimal parallelepiped” of the chain), components of the radius <S1>, <S2>, <S3> and square radius of gyration <S1
2>, <S22>, <S3
2>. It was shown that the values of <h>, <S2>, <S3
2>, <g3> decrease with an increase of chain unsaturation. The molecules with d double bonds (d=Const) localized near the center of the chain have the smallest <h>, <S2>, <S3
2>. Shape of all the chains investigated is asymmetric. Minimal parallelepipeds of the saturated chains are more extended and flatter than that of unsaturated ones with the same N. With an increase of d for N=Const the minimal parallelepiped of the chain becomes shorter (<g3> decreases) but thicker (<g1> increases). An increase of convolution of the chains with an increase of d is observed because the lowest energy conformation of n-alkanes is “trans-zigzag” whereas non-planar (more twisted) conformations are preferable in a chain with cis double bonds. Some experimental findings are discussed which support the results obtained. The results of our simulations indicate that both the shape and dimension of a chain are strongly affected by the chain length N and the presence and location of cis double bonds: a close relationship between these characteristics and the structure of the molecules is elucidated. This work was supported by grants Nos. 1642.2012.4, 1410.2014.4 for leading research schools of Russian Federation.
P-084 DNA COMPLEXES WITH DIVALENT CATIONS IN THE PRESENCE OF EDTA
P.A. Ushkov, A.I. Nikolaev, S.V. Paston
Saint-Petersburg State University, Faculty of Physics, Saint-Petersburg, Russia [email protected]
DNA interaction with divalent cations plays an important biological role and leads to interesting conformational transitions [1, 2]. In the present study we try to observe the reversible DNA complexation with some divalent metal ions due to their isolation by EDTA. EDTA (Ethylenediaminetetraacetic acid) is a polydentate ligand and a chelating agent. It is widely used for its ability to bind metal cations. Tetracharging EDTA anion coordinates cation through two amines and three or four carboxylates, acting as a penta- or hexadentate ligand. The stability of EDTA-cation complexes rises in the following order: Na+, Mg2+, Mn2+, Cu2+. In this work the disodium EDTA salt was used. At the neutral pH it presents in a solution in two forms: H2Y
2- and HY3- [3]. The experiment showed that EDTA does not affect the DNA secondary structure. It causes the rise of reduced viscosity of DNA solution with ionic strength 0.005M NaCl conceivably by the Na+ binding. EDTA-Me2+ complexes can be observed through their UV absorbance. DNA complexation with Mn2+ and Cu2+ was studied with the aid of CD (circular dichroism) and UV absorbance. We obtained wellknown spectral changes caused by divalent cations binding to DNA nitrogenous bases [2]. After adding EDTA to the solutions containing DNA and Me2+ we observed the recovery of CD spectrum of native DNA. We can suppose that it was the result of Me2+ scavenging by EDTA. One should mention that when EDTA binds a divalent cation one or two H+ are released into solution, so one should compensate the pH decrease either by using buffer solution or by addition of appropriate amount of NaOH. Only if the solutions containing DNA, Me2+ and EDTA remain neutral, one can obtain the recovery of CD spectrum of native DNA. Without H+ compensation we observed DNA protonation. As it was shown in [2] divalent metal ions are able to make complexes with DNA nitrogenous bases at acid medium by displacing H+ ions bound to ones. In our experiment there was no H+ displacement from DNA bases. It is another evidence that DNA bases were released from divalent cations by EDTA. The authors are grateful for the financial support from Russian Foundation for Basic Research (RFBR, grants 12-08-01134 and 13-03-01192) and from SPbSU (project 11.0.56.2010). References M. H. Shamsi, H-B. Kraatz. J. Inorg. Organomet. Polym. (2012) DOI 10.1007/s10904-012-9694-8. N.A. Kasyanenko, N.E. Dyakonova, E.V.Frisman. Molekularnaya Biologija (in Russian). (1989) v. 23, p. 975-982. 3. D. D. Perrin. Organic Complexing Reagents: Structure, Behavior, and Application to Inorganic Analysis. Interscience Publishers a division of John Wiley & Sons, New York. London. Sydney. 1964.
P-085 PERORAL SYSTEMS FOR DELIVERY OF THERAPEUTIC PROTEINS. COMPARISON OF BEHAVIOR OF MULTICOMPONENT
SYSTEMS IN SIMULATING MEDIA
E.V. Popova, N.N. Sudareva, O.M. Suvorova, N.N. Saprykina Institute of Macromolecular Compounds RAS
In our work, a comparison was made between structural and functional characteristics of various peroral delivery systems (DS) of antioxidant therapeutic protein (TPr) for the purpose of developing an effective peroral delivery system. The following carriers and their components were compared: N1 (calcium alginate granules), N2 (calcium alginate granules containing carbonate cores), N3 (carbonate cores encapsulated in multilayer polyelectrolyte alginate-gelatin shells) and N4 (untreated porous spherical carbonate cores (CaCO3)). Structural characteristics of DS (dimensions and morphology) were studied by scanning electron microscopy (SEM). Atomic composition of samples and location of the protein were determined from the data of energy-dispersive spectroscopy (EDS). The following functional characteristics of DS were studied: 1) therapeutic protein load (L), i.e. the amount of included TPr per unit of individual DS weight; 2) curves of TPr release into solutions simulating stomach and intestine media, i.e. time dependencies of TPr concentrations in these simulating media. The acid stomach fluid was simulated by 0.1 N HCl solution, and intestine medium was simulated by 0.07 N solution of phosphate buffer (PB) with pH = 7.9. The behavior of intact TPr and the protein labeled with fluorescent marker (dansyl chloride) was studied. Protein concentrations were determined by spectrophotometry, fluorimetry, EDS and high performance liquid chromatography. The latter method was used in order to estimate protein amount in solution containing polymeric components of DS. According to the SEM data, the mean size of the studied DS lies in the range from 3 μm (N3) to 100 μm (N1 and N2). The maximum value of TPr load was observed in the case of calcium alginate granules (L1=70 μg/mg, L2 =30 μg/mg and L3 = 50-60 μg/mg). Carbonate cores (Fig.1) are components of systems 2 and 3. They dissolve completely in the solution simulating stomach fluid during 30 min. In the PB solution simulating intestine medium, they are transformed into the structures presented in Fig. 2 during 24 h. EDS studies reveal the presence of phosphorus atoms in these objects and thus confirm the proceeding of the ion exchange (CaCO3 → CaHPO4).
Fig.1. Fig.2. Alginate is a biodegradable and biocompatible polymer widely used in medicine; it does not dissolve in acid stomach medium and protects TPr in all studied DS for 2 h. However, alginate swells and dissolves in alkaline intestine medium, and TPr is gradually released. SEM allows rendering degradation of various DS. The results observed in SEM images (morphology changes and increase in porosity occurring during DS degradation in stimulating media) correlate with TPr release profiles. Thus, after 4 hours of exposure to the intestine simulating solution, 90% of the protein was released from sample N1, 35% of the protein was released from sample N2 and 50% of TPr was released from DS N3. The comparison of the given characteristics of various DS demonstrates wide range of TPr load and release rate, this allows varying dosage and selecting convenient intervals of drug intake.
P-086 APPLICATION OF ENERGY-DISPERSIVE SPECTROSCOPY TO STUDIES OF DRUG DELIVERY SYSTEMS
N.N. Sudareva, E.V. Popova, N.N. Saprykina
Institute of Macromolecular Compounds RAS [email protected]
The usual field of application of energy-dispersive spectroscopy (EDS) is material science. In our work, EDS was used for the first time in the studies of objects designed for applications in medicine and biology (drug delivery systems for therapeutic proteins, DDS). The studied systems were prepared in the following manner. Porous carbonate cores (CaCO3) were synthesized in the course of coprecipitation of CаCl2 and Na2CО3 solutions in the presence of a protein; then these cores were coated layer by layer with polymers carrying opposite charges. The quality of DDS was evaluated from curves of proteins release into simulating stomach and intestine media solutions. In the present work, EDS was used in all stages of formation and evaluation of DDS. A Supra 55 VP scanning electron microscope (SEM) (Carl Zeiss, Germany) equipped with an INCA Energy 350 energy-dispersive X-ray spectrometer (Oxford) was used. The localization of protein in carbonate cores can be revealed by confocal laser scanning microscopy (LSM). The modern instrument (LSM 710 with argon laser) has a resolving power of 0.2 μm; for an object 5 μm in diameter (being the mean size of CaCO3 cores used as matrices for encapsulation), this is 4%. Besides, for LSM studies, an object should be “labeled”. Addition of fluorescent marker may change structure and functional activity of protein. EDS gives information about atomic composition within a volume of 1 μm3; localization of elements in carbonate core 5 μm in diameter is measured to an accuracy of 1.5%, i.e., resolving power of an EDS method is higher than that of an LSM method. In addition, localization and quantitative assessment of encapsulated object do not require specific treatment. In preliminary experiments, atomic compositions of 11 proteins were determined by EDS; these results were compared with the values calculated with the use of the known amino acid sequences. The disagreements did not exceed 10 %. For the proteins with unknown amino acid composition, atomic composition was determined. Protein localization in CaCO3 cores was established from the presence of atoms characteristic of proteins (N, S). Metalloproteins were additionally detected from the presence of corresponding metals. 1. The comparison between data of EDS studies of cores surfaces and splits demonstrated that higher amount of protein has been localized on core surface than inside cores. 2. The atomic composition of surface of СаСО3 matrix coated by polyelectrolytes with various molecular masses was studied. When dense coating was formed (which do not penetrate into pores), the content of nitrogen contained in gelatin (one of coating polymers) was higher on the surface than in the case of penetration of coating into pores. 3. The detected presence of Na and Cl atoms on the surface of polymer coating indicated ionic composition of solutions used in preparing polymer capsules and helped control the purity of finished capsules. 4. In the course of release experiments, EDS allowed to determine protein concentrations in simulating solutions, as well as revealed change in composition of СаСО3 matrices after exposing to phosphate buffer solutions (simulating intestine medium). The presence of P atoms in the matrices confirmed the proceeding of ion exchange reaction resulting in the formation of СaHPO4. SEM images showed considerable morphological differences between initial and final structures. It was demonstrated that EDS allows characterizing DDS in different stages of formation and functioning. Validity of the obtained characteristics was confirmed by SEM visualization of the studied structures.
P-087 POLYAMIDOIMIDE NANOCOMPOSITES WITH NI-NANOTUBES: PECULIARITIES OF STRUCTURE, MORPHOLOGY AND THERMAL
PROPERTIES
G.N. Gubanova1, M.E. Vylegzhanina1, A.Ya. Volkov1, V.K. Lavrentiev1, S.V. Kononova1, K.A. Romashkova1, S.I. Sinyova2, E.N. Korytkova3, T.P. Maslennikova3, T.E. Sukhanova1
1 - Institute of Macromolecular compounds RAS, Saint-Petersburg 2 - Saint-Petersburg State Polytechnic University
3 - Institute of Silicate Chemistry RAS, Saint-Petersburg [email protected]
In this study the investigation of nanocomposite films based on dicarboxyphenyl-phthalimide dichloride with 4, 4’-diaminodiphenyl ether (PAI) filled by hydrosilicate nanotubes Ni3Si2O5(OH)4 for development new polymer – inorganic membranes was carried out. Nanotubes of chrysotile structure with mean length L = 100÷200 nm, inner diameter 3 nm and outer diameter 15÷20 nm were synthesized by hydrothermal method [1]. The content of Ni- nanotubes (NT) was varied from 1 wt% till 7 wt%. For all composite films distinctive transition in temperature region 145-1600С, connected with local molecular chain mobility during evaporation of solvent, was determined. The maximum value of temperature for this transition was observed for neat PAI. The dependence of glass transition temperature - Tg on content of nanotubes is non-linear. The maximum value of Tg at 300˚ C is observed for composite films with 5 wt. % of NT. In addition, the dependence of thermostabily on NT content was NT content was investigated. By WAXD method the phase-aggregative state of composite films was studied. It was shown that PAI films is characterized by mesomorphic state (the reflection at 2θ = 3.9º and amorphous halo at 2θ = 19°40´ are observed). Introduction of NTs do not influence on structure of PAI matrix. When the content NT exceeded 2 wt% the reflections relevant to crystalline NT are observed against the background of halo, the intensity of these reflections are increased proportionally of NT content. Analysis of surface topography revealed that introduction of NT leads to smoothing of films surface, when NT content not exceeds 2 wt. % (the reliefs high is about several nm). The crystalline phase in AFM images in phase-contrast regime was not revealed up to 5 wt% of NT. In this case, claster-like, dendrite-like and fractal-like structures (Fig.1a, c) of NT associates were obviously observed on the surface, at the same time the reliefs high of the sample surface increases up to 100-150 nm (Fig.1b).
b
a c Figure 1. AFM images of PAI composite (7 wt% NT) film:
topography (a), profile (b) , 3D image (d). 1. Korytkova, EN, Maslov, AV, Pivovarova, LN, Polegotchenkova, Yu.V, Povinich VF, Gusarov VV. Synthesis of nanotubular Mg3Si2O5(OH)4 - Ni3Si2O5 (OH)4 hydrosilicates at elevated temperatures and pressures. Inorg.Mater.(Engl.transl. 2005; 41: 743-749.
P-088 INFLUENCE OF FIBROUS HYDROSILICATE NANOPARTICLES ON PROPERTIES OF POLYAMIDE-IMIDES COMPOSITES
G.N. Gubanova1, M. Cristea2, D. Timpu2, E.N. Korytkova3, A.Ya. Volkov1, T.E. Sukhanova1,
N.N. Saprykina1, K.A. Romashkova1, S.V. Kononova1 1 - Institute of Macromolecular compounds RAS, Saint-Petersburg
2 - Petru Poni Institute of Macromolecular Chemistry Romanian Academy of Science, Iasi 3 - Institute of Silicate Chemistry RAS, Saint-Petersburg
Development of organic-inorganic materials for advanced technologies, including membrane technology, is an actual problem of modern material science. In previous paper [1, 2] availability of use of nanotubular particles with chrysotile structure was shown, especially for pervaporation membranes based on thermally stable polyamidoimides (PAI). In this study physical-chemical and thermal properties of composites based on PAI matrices of different types, containing Na-Mg hydrosilicate nanoparticles of fibrous structure, are investigated. PAI’s synthesized from dicarboxyphenyl-phthalimide dichloride with 4, 4’-diaminodiphenyl ether (PAI-1) or 3,5-diaminobenzoic acid (PAI-2) were used. Inorganic Na2Mg4Si6O16(OH)2 synthetic fibrous hydrosilicate with a ribbon-chained structures (mean length of particles is 0.05-0.2mm, their thickness is about 10-100 nm) was synthesized by hydrothermal method [3]. It was shown that films of PAI-1 and composites based on PAI-1 possess anisotropy of mechanical properties, related with the polymer structure. Dynamical mechanical analysis of composites completed in temperature region (-150÷350ºС) revealed besides mean α-relaxation transition (270-290ºС) the existence of two secondary transitions: low temperature γ-transition, connected with residual water, and relaxation transition at 200ºС, connected with solvent evaporation and appearance of mobility of polymer polar group. Following heating above glass transition temperature leads to PAI-1 polymer orientation and formation of mesomorphous polymer matrix structure and as the consequence to Young’s modulus increase. Results of PAI-2 matrix investigation allowed to make a conclusion about considerably higher Young’s modulus of PAI-2 compared with that of PAI-1 (up to 10GPa) and their high stability in wide range temperature region. For composites based on PAI-2 matrix with fibrous hydrosilicate nanoparticles stability of Young’s modulus up to glass transition temperature also revealed (though their value is lower comparable with that of based polymer PAI-2). It was established by means of TGA/DSC methods that introduction nanoparticles of fibrous structure into polymer matrix did not lead to notable increase of composite thermostability and glass transition temperature comparable with basic polymer, as it was observed for composite with tubular nanoparticles of chrysotile structure [2]. Investigation of the nanocomposites films cross-section by SEM and AFM allows us to explain the decreasing of physical-mechanical properties of composites based on PAI-1 as consequence of the non-uniformity of nanoparticles distribution and bad adhesion between polymer matrix and nanofillers. According SEM data distinct distribution of nanoparticles attained in the case of PAI-2 polymer matrix. PAI-2 polymer matrix differs from PAI-1 matrix availability of carboxylic groups, capable of hydrogen bonds formation with functional groups of fibrous nanoparticles. It was made assumption that specific network structure of PAI-2 matrix allowed preserve high level of physical-mechanical properties in wide range of temperature region not only for polymer, but also for composites based on it. References: 1. Kononova S.V.,Korytkova E.N., Maslennikova T.P., Romashkova K.A., Kruchinina E.N., Potokin L.L. Russian Journal of General Chemistry 2010; 80:1136-1142 2. Korytkova E.N., Maslov N.V., Pivovarova L.N., Drozdova I.A., and Gusarov V.V. Glass. Phys. Chem. 2004; 30: 51-55 3. G.Gubanova, S.Kononova, S.Bronnikov, K.Romashkova, T.Sukhanova, E.Korytkova, D.Timpu, M.Cristea, V.Harabagiu (2014). Journal of Macromolecular Science, Part B, 53; 4, 555-567
P-089 EFFECT OF POLYMER MOLECULAR WEIGHT ON STRUCTURE AND MORPHOLOGY OF SELENIUM-CONTAINING NANOSYSTEMS
M.P. Sokolova, M.E. Vilegzhanina, A.A. Kutin, S.V. Valueva, T.E. Sukhanova
Institute of Macromolecular Compounds of the Russian Academy of Sciences, Bolshoy Pr. V.O. 31, 199004 Saint-Petersburg, Russia
Zero-valence selenium/polymer (Se0/polymer) nanosystems are very perspective for medical applications such as treatment of oncological diseases based on addressed drug delivery to sick organs, highly sensitive immunoassays biosensor and affinity chromatography reagents [1]. The perspective way for the preparation of such systems is the chemichal reduction of H2SeO3 by ascorbic acid in water solution of polymers. Polymer macromolecules adsorbed on the Se/solution boundary control particles dimentions and stabilize them against aggregation. Morphology of Se-based organic-inorganic nanostructures is very sensistive to the parameters of synthesis, among which the molecular weight of polymer stabilizator is one of the most important. In this study, Se0 nanoparticles stabilized by water-soluble polymer poly-N-vinylpyrrolidone (PVP) with different molecular weight (Mw = 10000, 29000 and 50000) were investigated by transmission electron and atomic force microscopy (TEM and AFM, correspondingly). In the Se0/PVP nanosystem prepared with Mw= 10000, two populations of nanoparticles with a quite different morphology and structure can be seen on TEM images (Fig. 1a). The first population is dense spherical particles mainly separated from each other, while the second one consist of spherical micelles agglomerates into bunchlike clasters with the shell thickness in the range of 2-4 nm. It is interesting that dimensions of both populations are practically the same and varying from 60 to 100 nm. It should be emphasized that this bunchlike clusters are very sensitive to electron beam irradiation. During TEM experiments, they survive with several seconds of exposure, then they are rapidly burning out. In result, micells with clearly seen shell and dense nucleus inside can be observed (Fig. 1a). The sizes of nucleus are in the range of 5-10 nm. It can be proposed that the dense structures and nucleus are the Se0/PVP nanostructures, as we have shown previously [2]. At increasing of PVP molecular weight up to Mw = 29000, the yield of micellar structures grows up while number of dense Se0/PVP nanostructures decreases. Also, dimentions of micellar structures decreases to 50-80 nm, as well as their number in aggregates. System with Mw= 55000 characterized by the formation of polygonal shape nanostructures with the average sizes about 100 - 200 nm as confirmed by AFM (Fig. 1b, c). So, the molecular weight of stabilizing polymer has a significant influence on the structural-morphological characteristics and properties of selenium-containing nanosystem.
a b c Figure 1. TEM image of Se0/PVP nanosystem with Мw = 10000 (a); AFM image of thin film prepared from aqueous solution of Se0/PVP nanosystem with Мw = 55000: topography (b) and profile (c).
1. Meshalkin Y.P., et al. // Biology. 2008. V. 1, Issue 3. P. 248-268. 2. Sukhanova T.E., et al. // Journal of Surface Investigation. 2014. V. 8, № 5.
P-090 IMMOBILISATION OF CHYMOTRYPSIN ON SELENIUM NANOPARTICLES
A.V. Titova, L.N. Borovikova, A.V. Kipper, O.A. Pisarev
Institute of Macromolecular Compounds,RAS,St.-Petersburg,199004,Russia [email protected]
The familiar methods of enzyme immobilization using polymer carriers are characterized by a common drawback: The polymer matrices create appreciable steric hindrances for an enzyme’s substrate diffusion, the attained increase in enzyme stability being accompanied by a reduction in its catalytic activity. The idea of enzyme immobilization on nanoparticles would seem to be promising, since a sharp increase in the specific surface of nanoparticles and the accessibility of sorption centers (compared to known carriers) should result in the multipoint interaction of an enzyme with nanoparticles, and hence to stabilization of its conformation. Moreover, the microencapsulation of nanoparticles in an enzyme polymer shell could help lower the hindrances to diffusion when the substrate shifts toward the enzyme active site. The hydrolytic enzyme chymotrypsin (CT) was selected due to its widespread use in medicine, biotechnology and food industry. Nanoparticles of selenium (Se) were chosen as carriers for CT. Selenium and its complexes with biologically active substances are of great interest as drugs with antioxidative, antiinflammatory and anticarcinogenic activity. Selenium nanocomposites with CT were synthesized during the reduction of selenious acid by ascorbic acid in aqueous media with pH of 2.8 to 3.5 at Т = 293 K and atmospheric pressure, according to the reaction:
H2SeO3 + 2C6H8O6 → Se + 3H2O + 2C6H6O6. (1) In the absence of CT, reaction (1) resulted in the formation of zerovalent red amorphous selenium sol and dehydroascorbic acid. The sol was unstable in solution, precipitating in ~24 h. Adding CT into reaction (1) simultaneously with the other components led to the formation of stable solutions with a reddish orange color. After synthesis in the presence of CT, selenium nanoparticles were maintained in a stable state in solution for 6 months, and the selenium did not change its modification after precipitation [1].This indicates that CT is an effective stabilizer of selenium nanoparticles in solution at acidic pH values when it carries a positive charge. The hydrodynamic radius (Rh) of stabilized nanocomplexes varied over a range of 70 to 410 nm. Their dimensions can be controlled by varying the amount of reducing agent during synthesis, the ratio of the concentrations of the reacting substances, and the pH of the medium [2]. We studied he aggregative stability of nanocomplexes in solution, depending on pH and parameter ν in the range of 0.5 to 10 (ν is the ratio of Se and CT concentrations, ν = CSe/CCT ). Nanocomplexes aggregatively stable in solution were observed in the acidic pH range (2.8–3.75) and the alkaline range (7.1–10.5). The pH values at when the full phase separation in the system was observed lay in the range of 3.75–4.0 to 6.5–7.0. pH intervals of the regions corresponding to full phase separation in the system were virtually independent of the concentration of selenium in solution. Only at high concentrations (ν = 8 and 10) did another range of the full phase separation appear at pH 10. It may be assumed that increasing the concentration of selenium to ν = 8 and 10 at a constant CCT concentration led to an insufficient density of CT molecule packing on nanoparticles. Hence, the interactions of nanoparticle parts not covered by CT molecules promoted their aggregation, the instability of nanocomplexes, and phase separation in the system. To establish the mechanism of nanoparticle stabilization, a NaCl solution of variable concentration was added to a solution of nanocomplexes with ν = 1. A gradually developing turbidity of solutions and the precipitation of nanocomplexes were then observed. Full phase separation (red precipitate and colorless solution) occurred when the salt concentration was 0.5 M. Adding Na2SO4 solution resulted in full phase separation at a salt concentration as low as 0.01 M, clearly demonstrating the electrosteric character of the nanoparticle stabilization. It was shown in that an enzyme bound to selenium nanoparticles retains its proteolytic activity, and even increases it in a number of cases (compared to a free enzyme). 1. L. N. Borovikova, A. V. Titova, N. A. Matveeva, and O. A. Pisarev //Russian Journal of Physical Chemistry. 2013. V. 87. No 6. P. 998-1001. 2. D. Yu. Ershov, A. I. Kipper, L. N. Borovikova, and O. A. Pisarev //Russian Journal of Physical Chemistry. 2013. V. 87. No 12. P. 2074-2076.
P-091 POLYPROPELENE FIBERS FILLED WITH CARBON NANOPARTICLES: PROSESSING, STRUCTURE, PROPERTIES
E.S. Tsobkallo1, A.N. Aleshin2, V.E. Yudin3, O.A. Moskalyuk3, E.M. Ivan’kova3
1 - St. Petersburg State University of Technology and Design, St. Petersburg , Russia 2 - Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg , Russia
3 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, St. Petersburg, Russia [email protected]
Composite materials based on the thermoplastic matrix filled with carbon nanoparticles in the form of fibers or films were obtained. Samples were drawn up to 8. The influence of type and concentration of carbon nanoparticles on the physical and mechanical properties of nanocomposites were studied. It is shown that nanocomposites filled with high axial ratio carbon nanoparticles have lower concentrations of percolation threshold. Orientation of anisotropic nanoparticles along the fiber axis is very important for improvement of physical and mechanical properties of composite fibers. One of the most important areas of research is the development of new polymer materials with special properties (antistatic, conductive, etc.). Introduction into various thermoplastic matrices of electrically conductive fillers is one of the most possible ways to obtain polymer materials with new properties. At the moment, the use of new carbon nanoparticles (carbon nanotubes, nanofibers, fullerenes), which have a complex of unique properties, is actual. The shape, size and dispersion of nanoparticles influence substantially on the properties of polymer nanocomposites. Moreover, the technology of their processing influence also on specific properties of materials. The aim of this work is the processing of nanocomposite based on polypropylene (PP) matrix in the form of the fibers or films, study of the influence of type and concentration of carbon nanoparticles on the physical and mechanical properties of nanocomposites. The PP of the brand Balen 01270 was used as the polymer matrix. Conductive fillers were: carbon black (CB) of the brand M-805E, vapor grown carbon nanofibers VGCF-H, multi-walled carbon nanotubes (MWCNTs) of the brand CTube-100 and single-walled carbon nanotubes (SWCNTs) SWCNT-60 obtained in IPCP RAS. Twin screw microextruder by company DSM Xplore (The Netherlands) with a special prefix for the preparation of fibers or films was used for processing nanocomposites. The samples of the nanocomposite fibers were drawn additionally up to 8 times at 150°C. It was shown, that dependence of the electrical resistance of films or fibers on the content of the carbon nanoparticles has a percolation type. Nanocomposites filled with high axial ratio carbon nanoparticles have lower concentrations of percolation threshold. For example, for fiber filled with MWCNTs the percolation threshold of the electric current is 0.5-1 wt%. For the films filled with the same filler a percolation threshold is 3-6 wt%. The nanoparticles effect significantly on the mechanical properties of oriented samples. The strength (σр) and deformation at break of an oriented films filled with CB decrease significantly. Strength of oriented fibers filled with anisotropic nanoparticles at the percolation threshold concentration (up to 3 wt.%) increases by ≈ 30%. Tensile modulus of PP fibers filled with VGCF or MWCNTs, SWCNTs increases by1.5-2 times. Strength (σр) of pure PP fiber is 370 MPa, PP fibers filled with 1 wt.% MWCNTs have σр = 440 MPa, PP fibers filled with 3 wt.% VGCF have σр = 500 MPa. By using SEM and X-ray scattering it was shown that, non-oriented fibers of pure PP have an isotropic structure and the absence of preferred orientation of the crystallites of the polymer. The filling of anisotropic particles causes an orientation of PP crystallites along the axis of the fiber. All fibers drawn up to 8 have sufficiently perfect crystallites. Crystallites are well aligned along the fiber axis. Anisotropic carbon nanoparticles do not cause change and disorientation of PP crystallites. Orientation of anisotropic nanoparticles along the fiber axis is very important for improvement of physical and mechanical properties of composite fibers. Large aggregates of carbon nanoparticles are formed in the PP matrix at high concentrations (more than 5 wt/%). It introduces defects in the polymer due to the difficulties of their uniform dispersing in the polymer melt, which leads to a reduction in strength of the fiber.
P-092 WATER SOLUBLE FORM OF PORPHYRIN DERIVATIVE: PROPERTIES IN DILUTE SOLUTIONS
E.B. Tarabukina1, E. Fagadar-Cosma2, I. Creanga2, N.V. Zakharova1
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia 2 - Institute of Chemistry Timisoara of Romanian Academy, Timisoara, Romania
Porphyrin derivatives show a range of amazing properties, which allow use these compounds in different fields. Due to their bio-compatibility they are prospective for bio-medical applications, in particular, as anti-fungi preparations. For this purpose porphyrins need to be transfered into water soluble form. One of the ways to introduce porphyrins into water solutions is their complexation with a water soluble polymer. A water soluble complex of 5-(4-pyridyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin and poly(N-vinylpyrrolidon) (PVP) was prepared. The complexation was confirmed using optical spectral analysis. An UV-vis study regarding the behavior of the hybrid porphyrin-PVP complex in acid environment was performed and demonstrated that the whole material is preserving porphyrin optical properties (Figure 1). The study of hydrodynamic and molecular characteristics of the complex in dilute aqueous solutions was carried out by means of viscometry, static and dynamic light scattering, and analytical ultracentrifugation. The intrinsic viscosity, sedimentation and diffusion coefficients, hydrodynamic radius, and also the specific partial volume and refractive index increment were obtained. Molar mass was calculated from the sedimentation and diffusion analysis and the light scattering. Supramolecular aggregative structures were found out in water dilute solutions, their size being dependent on the porphyrin content in the complex.
Figure 1. The behavior of hybrid porphyrin-PVP complex in acid media (initial pH=5; final pH=1.5) in DMSO solution, chybrid=4.4x10-6M
Acknowledgements: The work was partly supported by the Iinteracademic exchange program between the Russian Academy of Sciences and the Romanian Academy.
P-093 HYDRODYNAMIC PROPERTIES OF LINEAR PULLULAN STANDARDS. METHODOLOGY OF VELOCITY SEDIMENTATION
EXPERIMENTS AND VISCOMETRY
A.S. Gubarev1, O.V. Okatova2, G.M. Pavlov2 1 - Department of Physics, St. Petersburg State University, Ulianovskaya str. 1, St. Petersburg, 198504 Russia
2 - Institute of Macromolecular Compounds RAS, Bolshoy pr. 31 , St.-Petersburg 199004, Russia [email protected]
Polysaccharides belong to the central class of high-molecular compounds of natural origin, which play important biological functions within living substances. They are characterized by a structural and conformational variety caused by the particular features of the initial monosugars and the type of bonding into the polymer chain. The polysaccharide representative studied within the framework of this paper is linear pullulan (polymaltotriose). Pullulan is formed from yeast-like Aureobasidium pullulans micro-organisms. It consists of maltotriose units (α-D-glucopyranosyl-(14)-α-D-glucopyranosyl-(14)-α-D-glucose) linked by α-16 bonds. It finds quiet wide application in food and cosmetics industries as the substance capable of forming transparent films. Another area of pullulan applications is biophysical studies, where pullulan as water-soluble substance is used for calibration purposes in size exclusion chromatography (SEC). We have studied commercially distributed pullulan (SEC standard) produced by ‘Polymer Laboratories’ within wide range of molar masses: 5.9<MW10-3, g/mol<788 and average value of polydispersity index MW/Mn=1.12. Methods of molecular hydrodynamics were used for studying pullulan in dimethylformamide (DMF). All hydrodynamic characteristics were studied for this set of samples. Hydrodynamic invariant, sedimentation parameter and equilibrium rigidity were calculated. It was shown, that hydrodynamic characteristics of pullulan macromolecules in DMF are close to those, obtained for pullulan in aqueous solution [1, 2]. The comparison of intrinsic viscosities obtained with Ostwald and Hepler viscometers were made. The mixtures of pullulan with narrowly distributed samples were studied by velocity sedimentation for evaluation of SedFit software resolving possibilities [3]. Various models implemented in Sedfit cluster were used to derive the distribution of the samples in their sedimentation coefficients, and also for evaluating the average values of the sedimentation coefficients. The results show quantitative agreement of acquired data. 1. Pavlov, G. M.; Korneeva, E. V.; Yevlampieva, N. P. Hydrodynamic characteristics and equilibrium rigidity of pullulan molecules. Int. J. Biol. Macromol. 1994, 16, (6), 318-323. 2. Pavlov, G. M.; Yevlampieva, N. P.; Korneeva, E. V. Flow birefringence of pullulan molecules in solutions. Polymer 1998, 39, (1), 235-239. 3. Schuck, P. Size-distribution analysis of macromolecules by sedimentation velocity ultracentrifugation and Lamm equation modeling. Biophys. J. 2000, 78, (3), 1606-1619
P-094 INFLUENCE OF THE RHEOLOGICAL BEHAVIOR OF CNT-EPOXY POWDER COMPOSITION ON THE MECHANICAL PROPERTIES
OF FIBERS REINFORCED COMPOSITE MATERIALS
G.V. Vaganov1, J. Vuorinen2, V.E. Yudin1, V.Yu. Elokhovskii1, E.M. Ivan’kova1 1 - Institute of Macromolecular Compounds Russian Academy of Science, St. Petersburg, Russia
2 - Tampere University of Technology, Tampere, Finland [email protected]
Today, materials used in aerospace and aviation, automotive industry, shipbuilding and medical technologies need more demanding requirements. They are required to combine simultaneously high strength and rigidity, good resistance to dynamic loads, low weight, high values of long-term strength and provide increased reliability in construction. The incorporation of CNTs in polymeric matrices has attracted some attention in the research and industrial community due to their unique mechanical and electrical properties. One of the possible way to satisfy these requirements is the use of nanocomposites. However, one of the limitations in using CNTs as reinforcement for polymers is difficulty to obtain its uniform dispersion in the polymer matrix. Thus, a key issue in the processing of superior CNTs nanocomposites is the ability to control the dispersion of CNTs. There is a lot of information about improving the mechanical properties of liquid thermosetting resin as epoxy resins by their modification of CNT. However, the fiber reinforced composites based on epoxy powder compositions modified by CNTs and related literature is almost non-existent. This type of material is undoubtedly of great practical interest from both environmental and technical point of view. The aim of the present work is to investigate the changes in rheological behavior of CNTs/Epoxy composition on the mechanical properties of the carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP) based on them. Solid type epoxy oligomer (EO) Epicote-1004 was used as a matrix for the CFRP and GFRP. As a hardener we used a modified dicyandiamide trademark Casamid 780. The CNTs Baytubes C150P (multi-wall carbon nanotubes) type from the Bayer Material Science were used as nanofiller for epoxy resins. The diameter of CNT is ~ 15 nm, the length is less than 10 um. An unidirectional carbon fiber PORCHER-48299 (Porcher, France) and a nondirectional (mat) glass fiber reinforcements M621-300 (Alhstrom, Finland) were used for CFRP and GFRP, respectively. The dispersion of CNTs in the EO was carried out in two ways: by incorporation of CNT into EO melt by using a twin-screw extruder or by master batch dilution technique. In the first case, the powder of EO was mixed with various quantities of CNTs (the weight content varied from 0.1 to 2%) in melt in a double-screw extruder. Master batch dilution technique consists in following: the powder type mixture EO with 10 wt% CNT was dispersed in a double-screw extruder. Thereafter, highly concentrated batch of EO with 10 wt% CNT was diluted by pure EO by mixing in the melt to obtain any appropriate concentration of the CNTs in epoxy resin. The structure and degree of dispersion of nanoparticles in the epoxy oligomer was evaluated by rheological methods and SEM. It was found that the introduction of the CNTs in solid epoxy oligomers leads to a marked increase its viscosity and the appearance of yield point on the flow curve. Based on the rheological data, the most effective way to disperse the nanoparticles is the master batch dilution technique. The processing of CFRP and GFRP includes the spreading of powder compositions (EO/CNT/Hardener) on the fabric materials by the electrostatic method. For applying the CNT-epoxy powder to carbon fabric an electrostatic sprayer "Leader" was used, and for applying to glass fabric tribo sprayer "Tristan 100" was used. Then carbon and glass fabric with the polymer powder was treated thermally by rolling the obtained specimens through a thermostatically-controlled calender with the rolls heated up to 110�C. Such processed prepregs were stacked 18 plies and molded at a pressure of 1 MPa and 180C for 15 min to achieve the finished materials. The introduction of 1 wt.% CNTs in epoxy powder composition resulted in increase in fracture toughness, flexural strength and flexural modulus of both CFRP and GFRP. As it was shown also the master batch dilution technique is more effective method to increase the fracture toughness of CFRP and GFRP.
P-095 STUDY OF POLYMER COMPOSITES WITH WOOD DOPANTS
A.S. Nurtazina, A.K. Zhubaev, A.Z. Bekeshev Aktobe Regional State University
It is known that polypropylene has high crystallinity and rigidity. At the same time the use of filler will significantly increase its strength characteristics. In this paper the isotactic polypropylene granules (Balen 01270) were used for polymer matrix creation. The filler was produced from wood flour. The samples were prepared by melt technology using twin screw DSM Xplore 5 ml Microcompounder. The powder mixture of PP and wood flour in the given proportions was introduced in a micro shifter and stirred for 5 min at 200°C. Thereafter, the fibers were formed using 1 mm diameter die installed at output of micro-compounder. Prepared melt was injected in Optional Injection Molding Device by means of which the samples for mechanical tensile tests were obtained. The samples of pure melt of PP and the samples of polypropylene matrix with various concentrations of wood particles. In order to determine the quality of dispersion of the filler in the matrix volume the surfaces of samples of composite fibers were studied by means of scanning electron microscope PhenomG2Pro. The mechanical tests of obtained samples were performed. The results of investigations were discussed.
P-096 SILVER NANOPARTICLES FORMATION IN THE PRESENCE OF COVALENTLY AND NON-COVALENTLY MODIFIED CARBON
NANOTUBES
O.A. Pyshkina, N.S. Volosova, V.G. Sergeyev Moscow State University, Moscow, Russia
For many new applications, such as molecular electronics, photogalvanic elements, sensors, transistors etc., a low junction resistance between nanostructures is important for decreasing the sheet resistance. In order to decrease the junction resistance between carbon nanotubes (CNT) we propose to modify CNT covalently by carboxyl groups or non-covalently by polycarbonic acids, which are known to form stable coordinate bonds with silver nanoparticles, which in turn can be melted at low temperature in order to form cross-linked network consisted from modified CNT and silver nanoparticles with minimized junction resistance. Covalent oxidation of carbon nanotbes was carried out in 8 М H2SO4/8 M HNO3 mixture at 60 С in sonicating bath during different amounts of time. It was found that increase of oxidation time leads to the increase of dispersability of multiwall carbon nanotubes (MWCNT) in water (up to 0.2 mg/ml) and to decrease of their conductivity (approx. in one order of magnitude). IR-spectroscopy shows the presence of carboxyl and carbonyl groups on the surface of modified MWCNT. TEM analysis of modified MWCNT shows that increase of oxidation time leads to the decrease of MWCNT length and Raman spectroscopy investigations indicates that the amount of MNT surface defects doesn’t change with the increase of oxidation time. In order to prepare silver nanoparticles dispersions stabilized with modified MWCNT two approaches were used. The one of them consists from reducing of silver ions by sodium borohydride in the presence of modified MWCNT. However in was found that such approach leads to aggregation of silver nanoparticles. The second approach consists from addition of modified MWCNT to preliminary prepared silver nanoparticle dispersion and leads to formation of silver nanoparticles dispersion stabilized by modified MWCNT persistent during several months. Non-covalently modified carbon nanotubes were obtained by treating polycarbonic acids mixtures with MWCNT by ultrasonicating. It was found that such non-covalent MWCNT modification results in the increase of their dispersion ability in 1 order of magnitude comparing to the covalent MWCNT oxidation. MWCNT dispersion ability depends on polycarbonic acid molecular mass. The composite formation between carbon nanotube and polyelectrolyte was confirmed by IR-spectroscopy. Silver nanoparticles were obtained in the presence of MWCNT – polycarbonic acids composite dispersions. Silver nanoparticles diameter depends on molecular mass of polycarbonic acid. Nanoparticles formation process was monitored by electronic spectroscopy and compared with the one for nanoparticles formation in the presence only polycarbonic acid without MWCNT. Nanoparticles diameter increases in the case of MWCNT presence in the system. This work was carried out with financial support from Russian Basic Research Fund (№13-03-00605-а).
P-097 POLYANILINE BASED SORBENTS FOR REMOVING VIRUSES FROM SOLVENTS
M.A. Shishov1, M.V. Ivanova2, V.T. Ivanova2, E.I. Burceva2, N.N. Nosik2, N.G. Kondrashina2,
I.Yu. Sapurina1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St-Petersburg 199004, Russia
2 - D.I. Ivanovsky Institute of Virology, of Ministry of Health of the Russian Federation, Moscow, 123078 Russia [email protected]
Conducting polyaniline (PANI) is so-called “smart” sorbent. Main chain of PANI contains nitrogen heteroatom for that reason specific sorption process is possible. Conductivity and redox properties allow managing sorbent condition by applying electric potential. Beside of it PANI has all properties important for sorbent, it possess high thermostability, insolubility and could be received as a powder and porous matrix with high specific surface area. PANI is nontoxic and biocompatible for that reasons it could be used in biomedical applications. We report here the A and B influenza viruses sorption ability of polyaniline and its Ag composites. Also polio virus type 1 vaccine strain Sabin sorption was studied. PANI-Ag composites were obtained by Ag reduction of polyaniline from solutions containing Ag+. Silver was deposited on polymer in as spherical particles with 30-50 nm size; its mass fraction in composite is 15-20%. PANI with nanotubes or spherical particle morphology was used to receive Ag composites (Fig a). Its electrical conductivity and surface area properties were studied. Virus sorption intensity was defined by hemagglutination (HA) and infection titers of virus-containing fluid changing before and after virus contacts with sorbent. PANI-Ag composite demonstrate better results. For influenza virus 16-32 times recession of hemagglutination titers was observed, that means almost absolute removal of viruses from basic solution (Fig b). In case of polio viruses changing of solution infection titer due to viruses sorption was lgTCID50 for PANI and 2lgTCID50 for composites PANI-Ag, what testifies a perspective using such type of sorbents for viruses filtering.
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Fig. A) PANI-Ag composite, transmission electron microscopy. B) Viruses A and B sorption by PANI nanotubes and PANI-Ag composite. 1,2 – pandemic strain A/South Carolina/02/10 (H1N1)pdm09; 4,5 – reference strain B/Florida/04/06; 7,8 - Allantoic avian influenza virus A/Duck Primorie/2621/01(H5N2).
P-098 TRANSPORT OF SMALL MOLECULES IN POLY(PHENYLENE-ISO-PHTALAMIDE) - NANODIAMONDS MIXED MATRIX MEMBRANES
N.V. Avagimova1, Z. Pientka2, M. Trchova2, N.N. Saprykina3, A.M. Toikka1, G.A. Polotskaya3 1 - Saint-Petersburg State University, Department of Chemical Thermodynamics & Kinetics, Universitetskiy pr.26,
Saint-Petersburg, 198504, Russia 2 - Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky sq.2, Prague 162 06,
Czech Republic 3 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr.31, Saint-Petersburg, 199004,
Russia [email protected]
Membrane separation processes are an essential part of scientific and technical progress in many areas. Currently, the significant stage on the way of membrane processes application is the design of membranes with specific parameters as well as high permeability and selectivity. The incorporation of nanofillers into the polymer matrix can bring polymer nanocomposite with improved properties. Nanodiamonds (ND) are specific carbon nanoparticles of ~5 nm in diameter with a large and accessible surface containing functional groups. ND possess a lot of unique properties including superior thermal conductivity, hardness and high refraction index, therefore it is a promising material for various application. In the present work poly(phenylene-iso-phtalamide) (PA) was modified by incorporation of nanodiamonds (ND) in order to obtain novel mixed matrix membranes for gas separation and pervaporation. PA/ND nanocomposites were prepared by solid phase dispersing ND (up to 5 wt%) powder in PA matrix and dissolving in chlorophorm. Mixed matrix membranes were prepared by solvent evaporation from the PA/ND solution on a glass plate. Membranes morphology was studied by atomic force microscopy with tapping mode method. The gas permeability of five representative gases, N2, O2, H2, CO2, CH4, was measured at temperature range from 30 C to 100 C. Pure gas permeability coefficients were determined using a laboratory high vacuum apparatus with a constant-volume permeation cell. Selectivity of gas separation and some thermodynamic parameters such as the activation energies of gas permeation and diffusion as well as the heat of sorption of all gases were calculated. AFM shows that incorporation of ND particles in PA matrix leads to a significant increase in the surface roughness of membranes. Gas transport properties of PA/ND membranes change by increasing permeability and weak decreasing selectivity as compared with PA membranes. Rise of temperature increases permeability of all gases but decreases selectivity. Thus, it is established that nanodiamonds profoundly affect on the morphology and transport properties of PA/ND mixed matrix membranes. Acknowledgement. The work was supported by Russian Foundation for Basic Research (grant № 12-03-00522).
P-099 POLYMER COMPOSITES BASED ON PPO-, PBI-TITANATE NANOTUBES AND THEIR GAS SEPARATION PERFORMANCE
V. Giel1, J. Peter1, E. Pavlova1, G. Polotskaya2
1 - Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky sq.2, Prague 162 06, Czech Republic
2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr.31, Saint-Petersburg 199004, Russia
The gas mixture separation using membranes was emerged as an efficient technology with greatest potential due to the compactness and energy efficience. Recent studies showed that composite polymeric materials seems to be promising for industrial applications. Homogenous polymer membranes based on polyphenylenoxide (PPO) or polybenzimidazole (PBI) show high permeability but low selectivity. Therefore, we prepared polymer composites based on titanate nanotubes which were embedded in the commercially available polymers PPO and PBI in the next step. The nanotubes were synthesized in IMC AS CR and possess a unique tubular structure of nanometer diameter and a unique large length/diameter ratio. Because the diameter of the fillers is bigger than the size of the gas molecules, gases can adsorb in the nanotubes or permeate through the polymer. From the polymer solution dense membranes were casted using a doctors blade. Morpholgical studies were done by atomic force microscopy, transmission electron microscopy and scanning electron microscopy. Furthermore, permeability of the gases H2, O2, N2,CH4 and CO2 were measured under steady-state conditions using a time-lag apparatus and selectivities were calculated.
P-100 EFFECT OF HYBRID STAR-SHAPED MACROMOLECULES WITH FULLERENE C60 BRANCHING CENTER ON MEMBRANE PROPERTIES
G.A. Polotskaya, E.L. Krasnopeeva, L.M. Kalyuzhnaya, N.N. Saprykina, L.V. Vinogradova
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr.31, Saint-Petersburg, 199004, Russia
The combination of individual properties of polymers and nano-size fillers creates synergic characteristics for mixed matrix polymer materials, which makes them a group of promising materials for different application. Among the important application is membrane technology, namely, pervaporation technique for separation of problem liquid mixtures such as isomeric, azeotropic and so on. In the present work hybrid star-shaped macromolecules (HSM) were included in matrix of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) to create new mixed matrix membrane material and to study the effect of HSM on structure and transport properties in pervaporation. The HSM fillers consists of fullerene C60 molecule as a branching center and polystyrene and diblock copolymers poly-(2-vinylpyridine)-b-poly(tert-butylmethacrylate) as arms. The PPO/HSM mixed matrix membranes are intended for solving important practical problem (separation of mixtures of mono- and diatomic alcohols, ethylene glycol and methanol). According to scanning electron microscopy data, HSM inclusion in PPO matrix changes morphology of membrane surface. Domains are formed in membranes and their amount increases with the growth of HSP content. Mass transfer through PPO/HSM membranes was studied by sorption and pervaporation tests toward methanol and ethylene glycol. In the pervaporation of methanol–ethylene glycol mixture over the concentration range of 5 30 wt% methanol in feed, all membranes showed high affinity to methanol and produced the permeate concentrated in methanol. The total flux through membrane increased with the growth both the HSP content in membrane and the methanol concentration in the feed. The values of separation factor rose with increase of HSP content in membranes. The highest permeability of methanol as well as the highest selectivity and separation factor were achieved at 5% methanol in feed.
P-101 DYNAMIC SURFACE PROPERTIES OF LYSOZYME/SURFACTANT SOLUTIONS
M.M. Tihonov, B.A. Noskov
Saint-Petersburg State University, Saint-Petersburg, Russia [email protected]
Dilatational surface rheological properties of the mixtures of lysozyme with sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) were studied by the oscillating ring and oscillating barrier methods. The nonmonotonic dependency of the rate of change of the dynamic surface properties of lysozyme/SDS solutions variation rate on the surfactant concentration at the initial adsorption step can be connected with the change of the charge of the lysozyme/SDS complex at the increase of the binding degree of the surfactant [1]. Nonmonotonic kinetic dependencies of the dynamic surface elasticity indicate the destruction of the tertiary and secondary structures of the protein in the surface layer. The influence of the interface on the protein unfolding proves to be stronger for lysozyme/SDS solutions as compared with the surfactant/protein solutions investigated earlier. In the case of lysozyme/DTAB solutions the monotonic decrease of the rate of the change of the dynamic surface properties with the surfactant concentration was observed. This effect can be caused by the increase of the electrostatic adsorption barrier. The absence of local maxima of the kinetic dependencies of the dynamic surface elasticity leads to the conclusion on the preservation of the tertiary and secondary structure of the globule in the mixed solutions of lysozyme and DTAB. The work was financially supported by the Russian Foundation of Basic Research (RFFI No. 14-03-00670_a), the National Science Counsel of Taiwan (joint project RFFI-NSC No. 12-03-92004-ННС_а) and St. Petersburg State University (project No. 12.38.241.2014). References: 1. Noskov, B.A.; Tihonov, M.M.: Colloid Journal 74, 266, 2012.
P-102 FIXING THE DNA MOLECULES ON THE GOLD, MICA, AND SILICON SURFACE USING THE PHENANTHROLINE DERIVATIVE
P.A. Sokolov1, V.N. Demidov2, M.I. Osolodkov1, D.M. Nikolaev1, N.A. Kasyanenko1
1 - Saint Petersburg state university, Department of Physics, Saint Petersburg, Russia 2 - St. Petersburg State Technological Institute (technical university), Department of Chemistry, Saint Petersburg,
Russia [email protected]
The method of DNA fixation on mica surface with magnesium ions is well developed and widely used. It is often necessary to fulfill the fixation of DNA on alternative surfaces and the use of magnesium ions does not lead to a desired result. In particular, DNA fixation of on a gold surface must be done for the investigation of systems with surface plasmon resonance (SPR) method. Indeed, the study of DNA interaction with proteins and various ligands with SPR method requires the development of a technique for the preparation of chips containing DNA on the gold surface. Earlier DNA immobilization on the gold surface was carried out using 11-mercaptoundecanoic acid in the presence of divalent ions or by chemical modification of the oligonucleotides with S-containing groups. These methods are not suitable for a number of systems, so an alternative way was proposed in our work. It is necessary to underline that the fixation of high molecular double-stranded DNA on the gold surface is poorly developed. Similar difficulties arise in biochips fabrication and in preparation of DNA samples for microscopy. We developed a novel method for the immobilization of high molecular weight DNA on different surfaces (mica, glass, n- and p-type silicon and gold) using thiol derivative of phenanthroline (Phen-SH). First, Phen-SH adsorption from the solution on various surfaces was studied. Second, DNA interaction with modified surfaces was analyzed. The principal possibility of this method of DNA fixation on a surface for SPR chip preparation as well as for the creation of DNA samples for AFM and SEM techniques was confirmed. It may be useful for the creation and design of new biosensors based on DNA. The method based on DNA interaction with a phen-SH modified surface via complex formation in a solution. The molecular model of interaction is proposed. Experiments were performed using equipment of resource centers of Saint Petersburg State University Work was supported by a RFBR grant 13-03-01192A and SPbU grant 11.38.644.2013.
P-103 ELECTRODEPOSITION OF ULTRATHIN FILMS OF POLYANILINE–POLYSULFONIC ACIDS COMPLEXES AND THEIR
BIOLOGICAL APPLICATIONS
O.D. Omelchenko1, O.L. Gribkova1, A.A. Nekrasov1, A.A. Isakova1, V.F. Ivanov1, V.A. Tverskoy2, Yu.G. Bogdanova3, A.V. Vannikov1
1 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia 2 - M.V. Lomonosov Moscow State University of Fine Chemical Technologies, Moscow, Russia
3 - M.V. Lomonosov Moscow State University, Moscow, Russia [email protected]
In the present work, ultrathin films of polyaniline (PANI) complexes were obtained by aniline electrodeposition from aqueous solutions of polysulfonic acids of different structures. PANI electrosynthesis was performed in potentiostatic regime, smooth gold plates being as substrate. The polyacids include flexible-chain ones such as poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and poly(styrene sulfonic acid) (PSSA) and semi-rigid-chain poly-4,4’-(2,2’-disulfoacid)-diphelylene-iso-phthalamide-co-4,4’-(2,2’-disulfoacid)-diphelylene-tere-phthalamide (co-PASA). The “common” PANI film obtained in the presence of HCl solution was used for comparison. The films were characterized by cyclic voltammetry, spectroelectrochemical, AFM measurement, and surface plasmon resonance spectroscopy. The acceleration of aniline electropolymerization in the presence of polysulfonic acids in comparison to “common” PANI synthesis should be noted. The reason might be a high degree of aniline association with the polyacids. Moreover, changes in the shape of time dependences of charge and the rate of aniline polymerization according to polyacid used were observed. It was shown earlier that chemically synthesized PANI and PANI-PAMPSA complex presented good sorbents for different biological objects such as viruses and non-viral proteins [1]. The integrated investigation by surface plasmon resonance spectroscopy and AFM showed all electrochemically synthesized PANI complexes to be good substrate for bioobject adsorption (namely, cDNA of influenza viruses and influenza viruses as themselves). Hydrophobic/hydrophilic properties are of the great importance for interaction of solid surfaces with proteins of bioobjects. Obtained complexes are characterized by different hydrophobicity: advancing water contact angles at the PANI and PANI-PAMPSA are 81 and 62º respectively. Using tensiometry of human serum albumine aqueous solutions and its contact angle measurements at the films surfaces the more effective interaction of PANI-PAMPSA (in comparison to “common” PANI) with protein molecules leading to significant alteration of its native conformation was found. Moreover, it was shown, that structure of PANI complexes influences the sorbent capacity of biological objects. Obtained results could open new perspectives in PANI polymer complex application in biology. [1] Ivanova V. T., Ivanov V. F., Gribkova O. L., Kurochkina J. E., Matjushina R. O, Vannikov A. V., RU 2,372,951; 2009 The financial support of the Russian Foundation for Basic Research (grant No.14-03-31425 mol_a and 12-03-01087_а) is acknowledged.
P-104 EFFECT OF LIPID MOLECULE GEOMETRY ON STRUCTURE AND PROPERTIES OF POLYCATION COMPLEXES WITH NEGATIVELY
CHARGED LIPOSOMES
A.A. Efimova, D.A. Pyatnikova, A.A. Yaroslavov Department of Polymer Sciences, Faculty of Chemistry, M.V.Lomonosov Moscow State University
For last decades liposomes (spherical bilayer lipid vesicles) are widely used as containers for the targeted delivery of biologically active compounds. However, it should be noted that over time the lipids of which the containers are constructed may undergo a number of changes. For example, during storage the processes of lipid oxidation can take place. It is well known that in this case the geometry of lipid is changed. Preferably the oxidation of lipids produces surfactants containing one alkyl chain. This can lead to defect formation in the liposomal container and premature leakage of its content. The contact of polycation with the container may become irreversible. Therefore the aim of this study was to investigate the structure and stability of polycation complexes with oxidized liposomes using model system: liposome membrane with built-in surfactant containing one alkyl chain. Interaction of cationic polyelectrolyte, poly(N-ethyl-4-vinylpyridinium bromide) (PEVP) with small unilamellar anionic liposomes has been analyzed. We used mixed liposomes composed of neutral and negatively charged lipids of different geometry. We used phosphatidylcholine (PC) and n-hexadecylphosphocholine (HDP) as neutral components. The charged components were represented by: cardiolipin (CL), palmitic and heptanoic acids (PA, HA). HDP, PA and HA were used as sructural models of lipid oxidation products. PC is in cylindriform. The form of HDP, PA and HA molecule is turned cone. The influence of form of anionic lipids on the stability of polycationliposome complexes in water-salt media was investigated. The stability of the resulting complexes in water salt media and the integrity of the liposomal membrane in contact with the adsorbed polycation were found to be strongly dependent on the lipid form. The incorporation of neutral and negatively charged surfactants containing one alkyl chain into the liposomal membrane leads to the formation of defects and irreversible interaction with the polycation. These results should be taken into consideration for the description of membrane-polyelectrolyte interactions. Acknowledgements. This work was supported by Russian Foundation of Basic Research (project № 14-03-00717)
P-105 CONDUCTIVE POLYANILINE-GRAPHENE NANOCOMPOSITES
O.D. Omelchenko, O.L. Gribkova, A.R. Tameev, A.V. Vannikov A.N. Frumkin Institute of Physical Chemistry and Electrochemistry of the RAS
Design and preparation of polymer nanocomposites is one of the most perspective approaches in development of new materials with improved properties. In the report, the nanocomposites based on polyaniline (PANI) complex with polysulfonic acid and graphene are considered. For the preparation of the nanocomposites two procedures were used. The first one included the addition of graphene dispersions into polymerization medium in the course of the PANI synthesis, and the second one consisted in mixing PANI-polyacid and graphene dispersions. In the both cases, the distribution of graphene in the bulk of the nanocomposites was uniform as shown by transmission electron microscopy. Graphenes having different degree of oxidation, namely hydrophobic non-oxidized and hydrophilic semi-oxidized ones, were used. The addition of any graphene into the synthesis medium resulted in decreased polymerization rate of the PANI complex. This might be due to the interaction between graphene and growing PANI chains that hindered the aniline polymerization as the competition between semi-oxidized graphene and aniline for the interaction with polysulfonic acid was revealed. Even at a low concentration of graphene the conductivity of thin films of all the nanocomposites was found to (a) exceed that of the PANI complex and (b) markedly depend on the oxidation degree of graphene. The latter was observed for the first time: the conductivity increased by a factor of 3 and 20 for the nanocomposites comprising non-oxidized and semi-oxidized graphene, respectively. A mechanism of the charge carrier transport in the nanocomposites is suggested. It takes into consideration electronic interaction between graphene plane and PANI backbone as well as hydrogen bonding of graphene with functional moieties of the polysulfonic acid. The feasibility of using the developed nanocomposites as a buffer layer in polymer solar cells was demonstrated. Other possible applications of the materials are also discussed. The financial support from the Russian Foundation for Basic Research (grant No. 14-03-01137_а) is acknowledged.
P-106 MICRO- AND NANOCRYSTALLINE CELLULOSE MATERIALS AS BACKBONES FOR PROCESSING NEW CELLULOSE-BASED
NANOCOMPOSITES: FROM ENTIRE MATERIALS TO ADVANCED BIOACTIVE SUBSTANCES
N.E. Kotelnikova
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia [email protected]
One of great scientists told that any idea went through the three stages of development:
first, when they say: “this is not really”; second: “there is something in it”; third: “the whole world knows it for ages”.
This happened just with microcrystalline cellulose (MCC), and since the pionnering work of O. Battista [1], it is now well admitted that MCC consisting of anisometric particles is a substance with wide field for promising application. The processing and properties of MCC were then widely enlarged and profoundly investigated by FMC Corporation. FMC organized processing of MCC in an industrial scale [2]. The research on the properties and modification of MCC was begun in IMC RAS in 1966, included many collaborative groups and led to a number of publications and patents [3]. These investigations have initiated new research and have been extended to a nanotechnology range, which was defined as “the technology where dimensions or tolerances in the range 0.1 to 100 nm (from the size of an atom to the wavelength of light) play a critical role” [4], and have been evolved in various directions. One of them was the processing of new nanoscale materials on the basis of MCC. Three main prospective cellulose products, which already large-scaled in industry all over the world, have been obtained in the last two decades. They are as follows: microfibrillated cellulose (MFC), nanofibrillar cellulose (NFC) and nanocrystalline cellulose (NCC). All of them were derived from natural renewable products and were isolated from those by acid hydrolysis processing. The studies on MFC, NFC and NCC have been stimulated with new high-level instrumental methods. The most part of them has been devoted to their chemical and physical modification and application as substances with reinforcement potential to bio-nanocomposites, which exhibited promising properties. The term “nanocomposite” describes a class of two-phase materials where one of the phases has at least one dimension lower than 100 nm. The main reason in using cellulose nanofibers in composite materials is due to the potentially high stiffness of the cellulose fibers for reinforcement. The composite materials reinforced with them have found many potential applications in important fields like electronic and electrical industry, constructions, biomedicine and cosmetics, paper industry, packaging, building materials, textile industry and others [5]. Application of MFC, NFC and NCC in composites has many advantages. Nevertheless, their use is limited, due to that they admit from their strong hydrophilic character which causes the irreversible agglomeration during drying and agglomeration in non-polar matrices during composing [6]. To avoid these disadvantages, modification of the surface properties of MFC, NFC and NCC was applied using esterifying agents. Processing, properties, and applications of MFC, NFC and NCC and cellulosic-based nanocomposites, including a use branch as bioactive composites, will be discussed in this presentation. [1] Battista O.A. Encyclopedia Polym. Sci. Technol. 1967. Inter. Publ. N.-Y.; Battista O.A. Microcrystal Polymer Science.1975. McGraw-Hill. Inc. [2] http://www.fmc.com/ [3] Петропавловский Г.А., Kotelnikova N.E. Wood Chemistry. 1979, 6, 3. [4] A.B. Mabrouk, H. Kaddami, S. Bouti, F. Erchiqui, A. Dufresne. Cellulose. 2012, 19, 843. [5] A.N. Frohe, D.M. Panaitescu, D. Dohescu. U.P.B. Sci. Bull. 2011. B, 73, 2, 133. [6] P. Tingaut, C. Eyholzer, T. Zimmermann. www.intechopen.com
P-107 A ROUTE FOR THE IN VITRO SYNTHESIS OF CELLULOSE HYDROGEL/NANOSILVER COMPOSITE SCAFFOLDS FOR
BIOMEDICAL APPLICATIONS
A. Mikhailidi1, N. Kotelnikova2, E. Anan’eva3, Yu. Martakova4 1 - State University of Technology and Design, St. Petersburg, Russia
2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia 3 - St. Petersburg State Chemico-pharmaceutical Academy, St. Petersburg, Russia
4 - Institute of Chemistry, Ural Branch of RAS, Siktivkar, Russia [email protected]
Silver nanoparticles have been found to be a promising antimicrobial material. In this study highly stable silver nanoparticles have been directly synthesized to cellulose hydrogel as nanoreactor via in vitro redox process using silver nitrate. Cellulose itself or/and sodium ascorbate have been applied as reducers. Hydrogels with loaded silver nanoparticles form cellulose-silver nanocomposites. The presence of silver nanoparticles have been confirmed with X-ray diffraction method, XPS and SEM. SEM results revealed that the nanoparticles exhibit heterogeneous size distribution and rendered from 5 to 50 nm. The silver nanoparticles were very stable in the hydrogel cellulose matrix. However, due to their uncontaminated and developed surface, they seem to be very active. The antimicrobial activity estimated to hydrogel-silver nanocomposites was carried with respect to the strains of gram-positive Staphylococcus aureus 16 and gram-negative Escherichia coli bacteria. Microbiological tests have shown that the nanocomposites exhibited antimicrobial activity, and very low concentrations of silver nanoparticles were sufficient to positive bactericidal effect. Thus, silver nanoparticles loaded to cellulose hydrogels reveal formation of a new type of nanocomposites which can be applied as scaffolds for antimicrobial application.
P-108 DIELECTRIC RELAXATION IN COMPOSITE SYSTEMS BASED ON THE POLYDIPHENYLOXYDEAMIDO-N-PHENYLPHTALIMIDE AND
MG-HYDROSILICATE NANOTUBES WITH THE CHRYSOTILE STRUCTURE
N.V. Avanaseva1, S.V. Kononova1, K.A. Romashkova1, T.P. Maslennikova2, S.V. Gladchenko1
1 - Federal State budgetary institution of Science Institute of macromolecular compounds, Russian Academy of Sciences (IMC RAS), Saint-Petersburg
2 - Federal State Budgetary institution of Science Institute of chemystry silicates, Russian Academy of Science (ICS), Saint-Peterburg
Composites of the type of filled polymers are used not only in the formation of new construction materials, but also in the development of polymer membranes for industrial use, resistant to the harsh conditions of the separation process. However, general principles of compatibility of components and morphological properties of the composites have been still not widely studied, and they are researched at the moment. For decision this problem, method of dielectric spectroscopy, which is a sensitive indicator of the intra- and intermolecular interactions, can be used. In this study composite films based on polydiphenyloxideamido-N-phenylphthalimide
N
O
O
NHNH
OO
O
(PAI) n with tubular nanoparticles Mg3Si2O5(OH)4 of the chrysotile structure were investigated. The content of nanofillers in polymer composites varied from 2 till 10 m%. It is shown that for PAI and all of the composites two local dipole relaxation processes of the polarization with markedly different kinetic parameters are observed in a wide temperature and frequency range. Kinetic parameters of a low-temperature process are changed as a result of consecutive heating of the sample. It can be assumed that this dependence is related with the quantity of solvent in the system. A high-temperature local process was realized only when almost all of the solvent N-methyl-2-pyrrolidinone was removed from the test system. In addition, the local low-temperature process was shifted towards lower temperatures with increasing concentration of nanotubes, and its activation energy was lower. It should be noted that, being sufficiently large for local processes, the relaxation times of the high temperature process indicate a possible correlation of motion which may be both inside and interchain character. In this connection, the assumption can be admitted to the presence of inter-chain interactions and tendency to ordering in the system. For PAI and PAI - composition with 2 m% of nanotubes, non-relaxation process (relaxation times do not depend on the field frequency) was exhibited. From literary data [1] it is known there were areas with ordered structure in so-prepared PAI films. This process was not detected for compositions containing 10 m% of nanotubes. That is possible to associate discussed fact with impossibility of obtaining an ordered structure of the composite film in the case of its formation in the presence of nanotubes in a given amount. References: 1.G.Gubanova, S.Kononova, S.Bronnikov, K.Romashkova, T.Sukhanova, E.Korytkova, D.Timpu, M.Cristea, V.Harabagiu (2014) Nanocomposites Based on Polyamide-Imide and Magnesium Hydrosilicate Nanotubes, Journal of Macromolecular Science, Part B; Physics, 53:4, 555-567.
C
CH3
C O
O
CH2
CH2
NH3C CH3
m
O
NH
CH2OHOH
OH
OH
C O
CH2C
CH3 H2C
n
P-109 OPTICAL AND HYDRODYNAMIC PROPERTIES OF SILVER NANOPARTICLES STABILIZED BY 2-(DIMETHYLAMINO)ETHYL
METHACRYLATE AND 2-DEOXY-2-METHACRYLAMIDO-D-GLUCOSE COPOLYMER IN SOLUTIONS
A.A. Lezov1, T.N. Nekrasova2, L.N. Andreeva2, O.V. Nazarova2, M.A. Bezrukova2,
Yu. I. Zolotova2, E.I. Suvorova3, N.V. Tsvetkov1, E.F. Panarin2 1 - Saint-Petersburg State University, Department of Physics, Ulianovskaya ul. 3, Petrodvoretz, St.Petersburg, 198504
Russia 2 - Institute of Macromolecular Compounds RAS, Bolshoy pr. 31, St.Petersburg, 199004 Russia
3 - Shubnikov Institute of Crystallography RAS, Leninskiy pr. 59, Moscow,119333 Russia [email protected]
Unique optical, electrical, and medical properties of noble metal nanoparticles (NPs) attract attention of fundamental and applied researchers. Preparation of size- or shape-selected and stable NPs in different environments is an important problem. In present investigation AgNPs stabilized by copolymers (AgNPs/copolymers) were prepared by mixing aqueous solutions of 2-(dimethylaminoethyl) methacrylate (DMAEM) and 2-deoxy-2-methacrylamido-D-glucose (MAG) copolymer and AgNO3 at room temperature. DMAEM-MAG copolymers were obtained by free radical copolymerization of monomers in solution (AIBN, DMF, 60o C). MM of copolymers varied from 25000 up to 280000. The MAG/DMAEM aqueous solutions were colorless before reaction with silver ions and changed gradually to red-brown during
reaction times. The appearance of the surface plasmon resonance (SPR) peak at λmax = 415-425 nm is evidence of AgNPs formation. The shape of the SPR band is almost symmetrical, suggesting that the AgNPs are well dispersed and sphere-shaped. It was confirmed by transmission electron microscopy. The AgNPs/copolymer solutions are stable for several months. Dynamic light scattering (DLS), diffusion-sedimentation analysis, dynamic birefringence and viscometry data were used to compare the molecular and conformational characteristics of initial copolymers
and their complexes with AgNPs. Data on DLS show the presence (~ 2−3 % mass) of large colloidal particles. The remove of colloidal particles by centrifugation leads to decreasing part of AgNPs in the polymer. Decrease of the AgNPs portion is the more significant the higher MM of copolymer. It was established that MM of AgNPs/copolymer is closed to the MM value of initial copolymers, i.e. one macromolecule of copolymer takes part in the AgNPs stabilization. Formation AgNPs is accompanied by negligible increase of the root-mean-square sizes in comparison with those for the initial copolymers. The optical shear coefficients values of the solutions AgNPs/copolymers considerably exceed those of initial MAG/DMAEM solutions especially for lower molecular weight samples with higher AgNPs content. This work was supported by the Russian Foundation for Basic Research (12-03-00687) and by the Presidium of the Russian Academy of Sciences (Program № 24 for Basic Research).
P-110 STRUCTURE, MORPHOLOGY AND SORPTION PROPERTIES OF LIGNIN ION-EXCHANGERS
A.S. Antayeva1, A.A. Myrzakhmetova1, N.N. Chopabayeva2, K.N. Mukanov2
1 - Institute of Masters and Doctoral PhD, Abay Kazakh National Pedagogical University, Zhambyl str. 25, 050010, Almaty, Kazakhstan
2 - Laboratory of Engineering Profile, K.Satpaev Kazakh National Technical University, Satpaev str. 22, 050013, Almaty, Kazakhstan [email protected]
Novel nano-, micro- and macroporous ion-exchangers have been synthesized by chemical modification of lignin with epoxy-diane resin ED-20 and oligomer of epichlorohydrin with subsequent amination of intermediate glycidyl and chlorine derivatives. Influence of nature and ratio of interacting compounds, temperature and duration of modification on stricture, phase composition, morphology and physical chemical, sorption properties of sorbents have been studied by FTIR, high resolution SEM and TEM, XRD, DSC, DLS and porosimetry methods. XRD results testify to the presence of amorphous (80%) and crystal (20%) phases in initial lignin polymer. Identification of crystal component has shown the presence of cellulose. As hardly hydrolyzed polysaccharide it has strong chemical bonds with lignin cellular wall and it remains in vegetative tissue after acid hydrolysis. Calculated roentgenograms show high and low intensive reflexes corresponded to cellulose at 2θ=34-51° and 2θ=14-23° respectively. Decomposition of the narrowest and intensive peak (002) at 22,53° by Lorentz's functions allows to identify three types of cellulose structure: crystal linear, crystal deformed (bent) and amorphous. It is established that epoxidation and amination of lignin lead to decrease of crystallinity index of modified polymers (13-15%) in comparison with untreated sample (20%). It is apparently connected with decreasing of amount of cellulose crystal component and increasing of content of amorphous phase. Increase of molecular weight of polyamines also leads to decrease of crystallinity index of final products. It was found that isothermal annealing of samples at 135°С for 1-7 hours results to gradual increase of crystallinity index of initial polymer (23-28%) and products of its epoxidation (20-24%). The increasing of amount of crystal phase at heating is probably caused by growth of amount of oriented cellulose macromolecules due to their ordering. SEM and TEM images of sorbents testify to presence of isolated spherical, slit-like, tubular pores and their combinations ranging from several nanometers to tens of microns. Modification leads to decrease of SBET of ion-exchangers (9,2-5,2 m2/g) in comparison with initial polymer (14,5 m2/g) due to incorporation of epoxy and amine compounds into lignin inner and outer surface. Low size of SBET of lignin and ion-exchangers indicates on their macroporous structure. Mesopore size distribution curves show that ion-exchangers mainly contain mesopores with diameter 10-14 nm. Synthesized ion-exchangers were used for sorption of toxic metabolites from blood serum of diabetic retinopathy patients and laboratory rats with diabetes and pancreatitis. In vitro tests show that lignin ion-exchangers are capable to selective extract triglycerides, atherogenous fractions of cholesterol (LDL-C, VLDL-C), bilirubin, glucose, creatinine, urea and digestive enzymes – trypsin, lipase, alkaline phosphatase and also aminotransferase and aspartate aminotransferase from biological fluids without destroying of their proteinaceous and electrolytic composition. As a result of effective removal of carbohydrates, lipids and ferments their content reduced from pathological to the optimum compensated level or physiological norm. Due to these fine detoxication properties lignin ion-exchangers can be used as enterosorbents for correction of metabolic violations and decreasing risk of diabetes and pancreatitis.
P-111 MORPHOLOGY OF BIOACTIVE NANOSYSTEMS BASED ON PROTEINS: MODIFICATION BY SE0 AND ZNSE NANOPARTICLES
S.V. Valueva, G.N. Matveeva, M.E. Vylegzhanina, T.E. Sukhanova
Institute of Macromolecular Compounds of the Russian Academy of Sciences [email protected]
Creation of a new generation of bioactive materials for medical purposes is one of the most demanded directions in the modern bionanotechnologies. Modification of proteins, in particular, bovine (BSA), human serum albumin (HSA) and chymotrypsin (CT) by nanoparticles of wide-band-gap semiconductor zinc selenide (ZnSe) and nanoparticles of zero-valent selenium (Se0) is very perspective for increasing of their bioactivity. The main goal of our work is investigation of new nanosystems based on proteins modificated by ZnSe or Se0 nanoparticles – determination of their morphological characteristics by AFM, HREM and DLS methods. As an example, AFM images of the thin films prepared from water solutions of the Se0/CT nanosystems at the mass ratios ν = CSe/CCT = 1, 3 and 10 presented in Figures 1a-1c. Two populations of spherical isolated nanostructures with the average radius RAFM= 40 and 75 nm are detected at ν = 1 (Figure 1a) at the substrate surface. At ν = 3 (Figure 1b), the Se0/CT nanosystem forms continuous film containing nanostructures with the average radius RAFM = 35 nm. In the case of ν = 10, fractal aggregates with sizes of several µm (Figure 1c) generated by nanoparticles with RAFM = 35÷50 nm. The surface average roughness (Ra) decreased from Ra= 8.7 nm (for ν = 1), to Ra= 6.0 nm (for ν = 3) and Ra= 1.2 nm (for ν = 10). Such considerable changes in morphology and sizes of prepared nanostructures while ν increased can be explained by the increasing of hydrophobicity degree of the system. DLS study of the hydrodynamical radius dependence of Rh
*on ν demonstrated good correlation with AFM data [1]. Analysis of structure-morphological characteristics of such hybrid nanosystems from various proteins with nanoparticles [1, 2] has shown that the ZnSe/HAS nanosystem exhibits the lowest sizes and highly separated nanostructures as revealed by HREM image (Figure 1d). Spherical isolated nanostructures with radius from 3 nm to 10 nm can be observed. DLS data showed that the average dimension of the ZnSe/HSA nanostructures is Rh
* = 14 nm. Consequently, it is found that the modification of proteins by nanoparticles may be controlled and the broad spectrum of morphological nanostructures can be obtained.
a b c d
Figure 1. AFM image topography of the Se0/CT nanostructure: ν = 1 (a), 3(b), 10(c); HREM image of ZnSe/HSA nanostructure (d).
1. Sukhanova T.E., Valueva S.V., Vylegzhanina M.E., Ershov D.Y., Borovikova L.N., Pisarev O.A. Nanotechnologii: nauka i proizvodstvo. 2013. № 1 (22). P. 16-21. 2. Sukhanova T.E., Vylegzhanina M.E., Valueva S.V., at al. Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques. 2013. V. 7. No. 4. P. 671-679.
P-112 EFFECT OF ZIRCONIA NANOPARTICLES ON CRYSTALLIZATION PROCESS OF SEMICRYSTALLINE POLYIMIDE R-
BAPB
A.N. Bugrov1, E.M. Ivan’kova2, V.E. Smirnova2, O.V. Almjasheva3, V.E. Yudin2, V.M. Svetlichnyi2
1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004 Russia; Institute of Chemistry Saint Petersburg State University, Universitetskii pr. 26, 198504 Russia
2 - Institute of Macromolecular Compounds of Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004 Russia
3 - Saint Petersburg Electrotechnical University "LETI", ul. Professora Popova 5, St. Petersburg, 197376 Russia [email protected]
Interest in the synthesis of semicrystalline thermoplastic polyimide (PI) is caused by the ability to create binders for composite materials on their basis that are capable of crystallization in the volume of the composite. Due to formation of a fusible crystalline phase in the polymer binder, its initial heat distortion temperature is determined by melting temperature of the crystalline phase. Using semicrystalline thermoplastic polyimides enables to increase the real operating temperature limit of the actual products, compared with amorphous analogs. In this regard, the study of crystalline phase formation in the polymer and its preservation after polymer melting is of interest. In [1], it is shown that introduction of organic bisimides or inorganic carbon nanotubes in semicrystalline polyimide (R-BAPB) based on 1,3-bis(3,3',4,4'-dicarboxyphenoxy)benzene (R) and 4,4'-bis-(4-aminophenoxy)-biphenyl (BAPB) has an effect on its crystallization, the carbon nanotubes acting as nucleating agent of crystallization process. In this work the effect of zirconia nanoparticles on the crystallization process of mentioned polyimide was investigated. ZrO2 (3 wt.% Y2O3) spherical shape nanoparticles with 10±2 nm size and 140±5 m2/g specific surface area, obtained by the hydrothermal synthesis, were introduced in a semicrystalline polyimide matrix both at the stage of the polyamic acid formation (polyimide prepolymer) and in the prepared prepolymer. The rotary viscosimetry method showed that introduction of nanoparticles based on ZrO2 increases viscosity of the prepolymer and contributes to its structuring, probably due to the formation of hydrogen bonds between the polyamic acid and the hydroxyl groups of the nanofiller surface. According to differential scanning calorimetry (DSC) the crystallization of the polyimide R-BAPB, synthesized in equimolar ratio of monomers is not observed. At the same time for the composite obtained by introducing ZrO2 (3 wt.% Y2O3) nanoparticles during the synthesis of the prepolymer, endotherm melting of crystalline phase is fixed on the DSC curves at 320°C. To eliminate the effect of residual solvent on the process of R-BAPB crystallization, the sample was heated to 360°C and held at this temperature for 15 min before it is complete amorphization. After that, the composite is cooled to a crystallization temperature of the polymer (280ºC), and subjected to isothermal holding for 1 and 2 hours. Values of the melting thermal effects of the secondary crystallization phase amounted to 11 and 19 kJ/g, respectively. The stages of samples crystallization, amorphization and recrystallization were also confirmed by X-ray diffraction and scanning electron microscopy. The recrystallization rate increase of R-BAPB was observed for the sample obtained by mechanical mixing of the ZrO2 (3 wt.% Y2O3) nanoparticles with ready prepolymer, synthesized in a ratio 1.03 mol dianhydride : 0.97 mol diamine, compared to the unfilled polymer. Thus, obtained data evidence that the ZrO2-based nanoparticles act as nucleating agent of the semicrystalline polyimide R-BAPB crystallization processes. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002 References: [1] V.E.Yudin, V.M. Svetlichnyi, G.N. Gubanova, A.L. Didenko, T.E. Sukhanova, V.V. Kudriavtsev, S. Ratner, G. Marom Semicrystalline polyimide matrices for composites: crystallization and properties // Journal of Applied polymer sci. 2002. V. 83. P. 2873-2882.
P-113 DYNAMIC MODULI AND MOLECULAR MOBILITY OF THE R-BAPB AND R-BAPS TYPE POLYIMIDES
V. Toshchevikov1, V. Smirnova2, A. Didenko2, Vl. Elokhovskii2, V. Yudin2, Yu. Gotlib2
1 - Institute of Macromolecular Compounds, Saint-Petersburg, Russia; Leibniz Institute of Polymer Research, Dresden, Germany
2 - Institute of Macromolecular Compounds, Saint-Petersburg, Russia [email protected]
Polyimides are considered to be one of the most important engineering plastics which have a fascinating potential for technical applications due to their excellent thermal stability, mechanical properties, and chemical resistance [1]. In the present study, synthesis and dynamic mechanical analysis of two types of polyimides (R-BAPB and R-BAPS) have been performed. The R-BAPB polyimide is based on 1,3-bis-(3,3’,4,4’-dicarboxyphenoxy)benzene (R) and 4,4’-bis-(4-aminophenoxy)biphenyl (BAPB); the R-BAPS polyimide is based on 1,3-bis-(3,3’,4,4’-dicarboxyphenoxy)benzene (R) and 4,4’-bis-(4-aminophenoxy)diphenylsulfone (BAPS). Frequency dependences of the storage (E’) and loss (E”) tensile moduli of both R-BAPB and R-BAPS type polyimides have been measured in the temperature domains, which include the glass transition temperatures of the materials: from 199 C to 211 C for the R-BAPB type polyimide and from 206 C to 224 C for the R-BAPS type polyimide. The glass transition temperatures for the R-BAPB and R-BAPS type polyimides are Tg=206 C and Tg=215 C, respectively. It has been shown that the time-temperature superposition principle holds for both polyimides and the master-curves for the tensile moduli E’ and E” have been plotted. A theoretical analysis of the master-curves for the R-BAPB and R-BAPS type polyimides has been performed on the base of the method of spectral density function of relaxation times [2]. In this method the spectral density function of relaxation times includes contributions of different types of molecular mobility: short-scale torsion vibrations, bending motions of semiflexible chain fragments, regime of Gaussian subchains and reptation mobility of macromolecules. Molecular weights of the characteristic kinetic units of the R-BAPB and R-BAP type polyimides (the Kuhn segment and the chain fragment between entanglements) have been estimated. Additionally, frequency dependences of the storage (G’) and loss (G”) shear moduli for the R-BAPS type polyimide have been measured in the temperature domain from T=240 C to T=310 C, which is above the glass-transition temperature of this material. It has been shown that the time-temperature superposition principle holds for the R-BAPS type polyimide in this temperature domain and the master-curves have been plotted. A theoretical analysis of the master-curves for the shear moduli G’ and G” has been performed on the base of the spectral density function of relaxation times. It has been shown that the dynamic moduli G’ and G” measured in the temperature domain above the glass transition temperature are strongly influenced by the molecular-weight distribution of macromolecules. Theoretical calculations of the dynamic moduli based on the exponential molecular-weight distribution function with a power-type prefactor are in a good agreement with experimental data. The agreement of the theoretical results with experimental data demonstrates a great potential strength of the proposed theoretical method which can be used in the future for investigation of polyimides of different structures, including nanocomposites. This work was supported by the Russian Foundation for Basic Research (grant 11-03-00944). References 1. V.E.Yudin, J.U.Otaigbe, L.T.Drzal, V.M.Svetlichnyi. Adv. Comp. Letters 2006, 15, 137. 2. V.Toshchevikov, V.Smirnova, V.Yudin, V.Svetlichnyi. Macromol. Symp. 2012, 316, 83.
P-114 CATALYTIC HYDROGEN TRANSFER IN POLYMERIZATION
K.K. Kalninsh, E.F. Panarin Institute of Macromolecular Compounds RAS, Saint Petersburg, Russia
Hydrogen transfer in organic reactions, including polymerization, involves successive electron and proton transfer steps, which can be experimentally detected in studying excited complexes, exciplexes, by means of laser time resolved spectroscopy. In real-time thermochemical experiments, the stages of electron and proton transfer are usually inseparable and coalesce in one process of hydrogen transfer. For example, immediately after mixing the chloranil and p-phenylenediamine in polar methanol at low temperature the spectrum shows absorption bands of radical anions and radical cations. An increase in temperature initiates proton transfer followed by the polycondensation reaction. However, in most chemical systems, no radical species are detected in the course of reactions, which encourage researchers to treat chemical transformations without implying the occurrence of electron and hydrogen transfer. We developed the notions about the mechanism of hydrogen transfer in specific electronically excited diradical states, which can be experimentally and theoretically studied. This brings about the question of the catalytic properties of the hydrogen atom transfer reaction. The major factor is suggested to be proton donor–acceptor interactions, which, in combination with electron donor–acceptor (EDA) interactions in the excited state, account for the decrease in Ea to the range of thermal values (less than 1 eV). Quantum-chemical calculations were performed with the GAMESS and Gaussian09W program packages by ab initio RHF, ROHF, and GVB methods with the use of the DH, SBK(d,p), SDD and 6-31G(d,p) basis sets. The planar complex p-benzoquinone-hydroquinone in solution (without hydrogen bond) and crystal (with a hydrogen bond) gives rise to the absorption band at, respectively, 24 000 and 17 000 cm-1 (the shift is 7000 cm-1). A further decrease in the CT energy is observed in inclusion complexes in which the insertion of solvent molecules into the crystal lattice of the complex lowers the state of the hydrogen bond. The maximal low frequency shift in this case is 11 000 cm-1, and a fine crystalline suspension thereby becomes blue color. A clear correlation between the hydrogen bond state and the CT band position in near IR region (5000–7000 cm-1) has been demonstrated by X-ray crystallographic and optical studies of EDA inclusion complexes of tetracyanoquinodimethane with benzidine. These and other studies deal with vertical optical transitions. Emission spectra of equilibrium excited states, active in thermochemical reactions, as a rule, cannot be detected because of almost complete quenching. Therefore, quantum-chemical calculations become a major source of information on the nature and energy of these excited states. The simple estimates support the conclusion that the hydrogen transfer reaction is catalyzed both by the external catalyst agent and by means of conjugation of EDA and PDA interactions in the reaction complex. From the standpoint of the nature of elementary stages, the suggested catalytic mechanism occurs in any reactions of reagents containing mobile hydrogen capable of forming hydrogen bond between π-electron systems and involved in the chemical process. Thus, the conjugation of two π-electron systems of the donor–acceptor complex through the common hydrogen atom sharply decreases the energy of the excited electronic state (Ea ) down to zero or even negative values and thus catalyzes the hydrogen transfer reaction. In the case of bifunctional catalysis, hydrogen transfer occurs through the bridging acid molecule acting as the catalyst. In this case, electronic excitation involves both molecules of the hydrogen donor and acceptor, which are not directly bound to each other. This conclusion follows from the distribution of free valence indices F. The ground state of the reaction complex is not involved in the hydrogen transfer reaction and forms only weak intermolecular donor-acceptor and hydrogen bonds.
P-115 ANALYSIS APPROACH FOR THE HYBRID POLYMER-INORGANIC NANOPARTICLES IN SOLUTIONS
N.P. Yevlampieva, M.Yu. Antipov, E.I. Rjumtsev
St. Petersburg State University, Physics Faculty [email protected]
Development of new nanocomposite polymer materials and improvement of those available are the important trends in modern materials science. As a rule, weight fraction of hybrid nanoparticles in composite polymers is small for the analysis of hybrids structure in a bulk state. An alternative way for investigation of organic-inorganic components of composite polymers may be realized through a study of such composites in diluted solution. Not far ago a great progress in producing of polymer-inorganic oxide (SiO2, TiO2, ZrO2) composite materials have been achieved when the oxides distribution inhomogeneity problems, such as a prevention of their aggregation and build-up of a sufficiently high adhesion at the polymer—inorganic particle interface, were overcome due to of special chemical modification of particles surface prior to their incorporation into polymer. By means of the required functional groups formation on the surface of inorganic particles a covalent linkage between the polymeric and inorganic components can be achieved. This methodology was successfully realized for a range of polymers, and polymer-inorganic composites containing nanocrystals or particles of SiO2, TiO2, ZrO2, Ag and Au with novel physico-chemical properties were developed [1, 2]. In the present work a methodical approach for analysis of structural details of polymer-inorganic particles with the covalent linkage between the components in solution is suggested. Its efficiency was demonstrated for fully soluble modified poly(methyl methacrylates) (PMMA) as an example of composite polymers containing hybrid inorganic-polymer nanoparticles. PMMA samples contained the covalently bound nanocrystals of zirconium dioxide that have two shells. The first shell of zirconium dioxide core was formed by a layer of low molecular modificator of surface, and the second shell was organized by PMMA-molecules covalently attached to modificator layer. The approach is based on the use of viscometry, dynamic light scattering and absorption spectroscopy for comparative study of the unmodified polymer and its analogue containing a small weight fraction (~0.01-0.02) of the hybrid particles. The methodology permits to estimate polymer component mass that is covalently linked with the inorganic component, and an averaged number of polymer branches in the case core-shell hybrid nanoparticles. That type analysis is very useful for the development of well soluble polymer-metal oxide composites. Practical usage of composite materials with the covalently bound nanoparticles is often faced with the necessity to give a preference only soluble well one. The requirement solubility is also dictated by a perspective of multiple utilization of the hybrid polymer-inorganic nanoparticles or necessity of theirs reselection. Authors are grateful to Dr. Alexander Bugrov (Chemistry Faculty, St. Petersburg State University) for providing the PMMA-composites with zirconium dioxide nanocrystals. [1] Vollath, D. Nanomaterials: An introduction to Synthesis, Properties and Applications (Wiley: New York, 2008). [2] Bugrov, A.N. Polymer-inorganic composites based on carbo- and heterochain polymers modified by ZrO2 nanoparticles. PhD Thesis, St.Petersburg (2013).
P-116 THE SYNTHESIS OF APPLIED NANO-CATALYSTS OF LOW-TEMPERATURE CARBON MONOXIDE OXIDATION
T.Kh. Rakhimov, M.G. Mukhamediev, B.Sh. Khakimjanov
National University of Uzbekistan named M.Ulugbek, Tashkent, Uzbekistan Republic [email protected]
The nano-clusters of platinum group compounds, palladium in particular, were synthesized by applying of salt water solutions onto various carriers with subsequent alkaline processing and soft reduction. It is shown that 5 to 10000 nm sized nano-particles are formed. The particles size and their homogeneity are determined by both the carrier’s nature and synthesis conditions. In particular, no nano-particles generation was observed when using carriers with active functional groups forming strong complexes with metal ions. It was found out that carrier should have a limited number of active functional groups and at the same time possess highly developed active surface in order to successfully synthesize the nano-compositional materials. Various inorganic carriers (aluminum-silicate, aluminum oxide, aluminum-chrome etc.), polymeric fibers and largely low-module carbon fibers meet such requirements. The latter possess the lowest number of active functional groups, and at the same time have the most developed specific surface among materials known nowadays (table 1). Evidently it is the 10 to 10000 nm sized nano-particles of platinum group compounds that are able to be catalytically active in low-temperature oxidation of carbon monoxide and formaldehyde. The activeness was growing along with the growth of 10-100 nm sized nano-particles’ proportion. As it is shown before (1) the process flows in self-oscillating mode. Table 1.The relative content of nano-particles in composite materials based on carbon fibres
Relative content of nano-particles (%), nm Static exchange capacity by benzene,
mg/g
Activeness in CO oxidation, 105mole/l*s*g <10 10-100 100-1000 >1000
4,25 0,2 1 9 35 55
25 0,7 5 20 35 40
120 1,4 10 30 40 20
180 2,6 5 40 30 25
275 2,8 8 50 12 30
450 3,8 5 60 15 20
480 4,2 5 60 25 10
The received nano-complexes own a unique catalytic activeness in relation to such chemically noble gases as carbon monoxide while it has extreme low concentration in air. And this offers a principally new way of solving ecological problems. 1. T.Kh.Rakhimov, B.Sh.Khakimjanov. Polymeric fibrous nano-complexes as highly active catalysts of low-temperature oxidation. – 6th International Symposium Molecular Order and Mobility in Polymer Systems. St.Petersburg, 2008. – p. 162.
P-117 NEW FUNCTIONAL PROPERTIES OF DETONATION SYNTHESIS NANODIAMONDS
A.A. Isakova1, B.V. Spitsyn1, N.A. Skorik2, M.V. Ivanova3, Yu. V. Kostina4, N.N. Nosik3,
A.V. Vannikov1 1 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia
2 - Tomsk State University,Tomsk, Russia 3 - D.I. Ivanovsky Institute of Virology, Ministry of Health, Moscow, Russia 4 - A.V.Topchiev Institute of Petrochemical Synthesis RAS Moscow, Russia
The paper discusses the surface modification of detonation nanodiamond (DND) powders (SINTA Co, Belarus) with various functional groups. Nanodiamond surface was subjected to graphitization in a wide range of temperatures, and also have active groups such as -COOH,-NH2,-Cl. Also the polyaniline grafting have been used. Physico- chemical, biological and sorption properties by transmission electron microscopy, dynamic light scattering , infrared spectroscopy and potentiometry were investigated. For determination of influenza virus and poliovirus ( Sabin type 1) sorption complex virological methods have been used. Composition of the functional groups on the surface before and after the nanodiamond inoculation was revealed by IR spectroscopy. Increasing graphitization temperature from 800 to 900 ° C leads to reduction in the CH2-groups number and provide higher acid group content , and amido and –CH3 as well. Graphitization at 1000 ° C is accompanied by an increase in the content of oxygen groups of the ketone and ester nature. The surface modification of nanodiamond by amino and carboxyl groups is an increase in the relative bands in the spectrum. Nanodiamond surface treatment among CCl4 leads to the band at 756 cm 1 attributed to the –Cl contents fluctuations.. Kinetic curves of protons desorption from nanodiamond particles surface as a function pH-τ (pH decreases over time ) was used to estimate the values of pK1 of nanodiamond surface acid sites . Graphitization of the surface leads to a slight decrease in pK from baseline nanodiamond samples . The lowest value of pK = 1.23 observed for DND samples , chlorinated atmosphere of purified argon. Change in the surface composition of the functional groups provide new functional properties, e. g. the viruses adsorption . The adsorption of viruses in water solutions increased in the case of the NH2 and Cl groups modification of the DND surface. The concentrations of viruses in solutions before and after contact with sorbents were estimated in hemagglutination (HA) titers for influenza virus and infection titers for poliovirus - the virus which causes polioviruses. The HA titers of influenza viruses decreased in 8 till 500 times after contact with sorbents. Infection titers of poliovirus decreased not more than 2.5lgTCID50. This work was supported by a grant of MK-3937.2013.3 ; the Cooperative Agreement N1U51│P000527-01, CDC&P, USA.
P-118 MODELS OF MACROCHAIN GROWTH ON ORGANOMETALLIC COMPLEXES AND INFINITE-MEMORY PARADOX IN CLASSICAL
MARKOV DESCRIPTIONS
V.A. Lovchikov, V.M. Rodin FSUE "ISR"
Conflicting evolution period of physical-chemical conceptions of formation processes of synthetic polymers, which began with the epoch-making discovery of catalytic stereospecific by Ziegler and Natta, cannot be completely finished. It is generally accepted that the sequence of the stereochemical configurations in the polymer chains obtained by organometallic complexes, cannot be described by first-order Markov statistic or by Markov statistics of any finite order [1]. It means that the model parameters corresponding to the experimental data obtained from high-resolution NMR spectra cannot be found by means of the classical description of the Markov chain growth and the consistent consideration more long-term effects of structural differences. For example, “non-Markovian” Coleman-Fox model for Grignard- or metal-alkyl-initiated polymerizations of acrylates [2] and other descriptions [3]. In this paper these model descriptions are considered, and causes of conceptions of non-Markovian character of the catalytic chain growth by organometallic complexes are analyzed. 1. F.A. Bovey, P.A. Mirau, NMR of polymers, San Diego Acad. Press, 1996. 2. B.D. Coleman, T.G. Fox, J. Chem. Phys. 1963, 38(5), 1065. 3. V.A. Lovchikov, Zhurnal obshchei khimii (in Russian) 1988, 58(3), 721.
P-119 MULTIPLE MORPHOLOGIES OF PEO/P3HT NANO-FIBERS FABRICATED BY TWO-FLUID COAXIAL ELECTROSPINNING
TECHNIQUE
P.Y. Chen, S.H. Tung National Taiwan University, Institute of Polymer Science and Engineering, Taipei, Taiwan
Two-fluid coaxial electrospinning technique is applied herein to fabricate poly(ethylene oxide) / poly(3-hexylthiophene) (PEO/P3HT) nano-fibers. The outer fluids are PMMA solutions while the inner ones are PEO/P3HT solutions. As the solvents are evaporated, PEO/P3HT nano-fibers surrounded by PMMA are formed. The morphology of the obtained nano-fibers were viewed under scanning electron microscope (SEM) transmission electron microscope (TEM).Various morphologies of PEO/P3HT nano-fibers can be created by the use of the combinations of different solvents, including chloroform (CF), chlorobenzene (CB), bromobenzene (BB) as inner and outer solvents, including the core/shell structure, the uniform structure and the ribbon-like structure. The organic field-effect transistor (OFET) carrier mobility of aligned PEO/P3HT nano-fibers could be improved up to 2 orders of magnitude (3.33×10-2cm2V-1s-1) in comparison with aligned pure P3HT nano-fibers (1.92×10-4cm2V-1s-1)
P-120 EFFECT OF FULLERENE C60 ON THE DIELECTRIC BEHAVIOUR OF EPOXY RESIN AT LOW NANOFILLER LOADING
D.V. Pikhurov1, V.V. Zuev1,2, S.V. Bronnikov2, V. Musteata3, D. Timpu3
1 - National Research University of Information Technologies, Mechanics and Optic 2 - Institute of Macromolecular Compounds
3 - Petru Poni Institute of Macromolecular Chemistry [email protected]
Using broadband dielectric spectroscopy, we examined the effect of fullerene C60 on molecular mobility of epoxy nanocomposites containing 0-0.12 wt.% of fullerene. In spite of small amount of fullerene addition (< 0.1 wt.%), Young’s modulus and tensile strength of these nanocomposites have been shown to increase in ca. 10%. The impact strength G has also been shown to increase with increasing fullerene C60 concentration. The 0.12 wt.% fullerene C60 loading has been found to increase in G three times: from 38 kJ/m2 (for neat epoxy resin) to 115 kJ/m2 (for nanocomposite). The temperature dependences of dielectric loss of the fullerene/epoxy nanocomposites measured at different frequencies are similar to those of neat epoxy and ascertain two principal relaxation processes: β and α. The values of relaxation times of the nanocomposites indicate a decrease of molecular mobility in the glassy state. Such results can be explained by significant interactions between nanofillers and molecular entities of epoxy matrix. Hence, introduction of fullerene in epoxy matrix leads to restriction of molecular motions. Since the distance between cross-links in these nanocomposites can be accepted as epoxy molecule size (2-3 nm), these particles may be involved in motion with the matrix molecules at similar time and length scales. As a result, fullerene hampers the molecular motion in epoxy composites. This leads to polymer chain hardening and impedes secondary relaxation process. This explains an increase in Young’s modulus of the nanocomposites. We found that the activation energy of β relaxation process in epoxy resin decreases with the fullerene loading. This finding allows us supporting the energy-dissipating mechanism explaining enhanced toughness of nanocomposites. According to this mechanism, a decrease in the activation energy of β relaxation process indicates an increase in the energy dissipation in polymer matrix. In addition, the decrease in the activation energy of β relaxation process indicates an increase in the nanoparticles mobility, which makes a valuable contribution to other mechanisms of the nanocomposites toughness, such as nanoparticles debonding and nanoparticles pull-out. Acknowledgements: This work was partially financially supported by Government of Russian Federation, Grant 074-U01.
P-121 INVESTIGATION OF SOLUTIONS AND FILMS PROPERTIES OF WATER-SOLUBLE CELLULOSE ETHERS’ MIXTURES WITH
ZOSTERINE
Yu.G. Santuryan, L.I. Kutsenko, L.M. Kalyuzhnaya, E.N. Vlasova, I.V. Gofman, I.V. Abalov, E.F. Panarin
IMC RAS, St.Petersburg, Russia [email protected]
In connection with the search of new polymer systems based on natural polymers for the biomedical purposes the study of compatibility and physical-chemical properties of two-component mixtures of methyl cellulose (MC), hydroxyethylcellulose (HEC) and Na-carboxymethylcelluloses (NaCMC) with zosterine in solutions and films has been carried out. Zosterine presents the natural polysaccharide, isolated from an eelgrass Zostera marina; it belongs to the class of pectins. Zosterine possesses a high sorption activity in relation to heavy metals and other toxicants and finds the wide application in medicine; however, it is incapable to films formation. MC, HEC and NaCMC are water-soluble biodegradable polymers and they do not harmful influence on a living organism. Ones are widely applied in pharmaceutical industry and possess good film-forming properties. Introduction of zosterine in a matrix of cellulose ethers gives the possibility to receive film materials with a new complex of the physical- chemical properties differing from properties of single-component films of these polysaccharides. Character of intermolecular interaction of polymers in water solutions of mixtures has been determined by a way of comparison of experimental dependences of viscosity and heat of activation of a viscous current of solutions Ea versus composition of mixtures with the calculated values received by an additive method. For diluted (0.3%) solutions of the studied mixtures the negative deviation of experimental dependence of viscosity versus the mixture composition from calculated values has been observed, that can be evidence to poor compatibility of polymers in such solutions. In moderately concentrated solutions (2.0%) of mixtures MC-zosterine and HEC -zosterine a positive deviation of experimental values of viscosity and heat of activation of a viscous current of solutions from additive values is observed that indicates to realization of intermolecular interaction of heterogeneous polymers due to the formation of system of H-bonds and an increase in strength of structural elements in solution. This conclusion has been confirmed by IR spectra of films of the studied mixtures. For system NaCMC -zosterin the dependence of experimental values of viscosity and heat of activation of a viscous current of solutions on composition of mixtures has a negative deviation from additive values that point to incompatibility of polymers in moderately concentrated solutions. Study of compatibility of polymeric couples in films by the method of solvent vapors sorption testifies on thermodynamic compatibility of components of mixtures MC-zosterine and HEC --zosterine and incompatibility of components in films of mixtures NaCMC -zosterine. Physical-mechanical tests have been showed that MC-zosterine films with the content of the last in mixture to 30% possess the high strength and satisfactory deformation properties. Mechanical characteristics of films HEC-zosterine (to 30% zosterine in mixture) are also high enough for their practical use. NaCMC-zosterine mixtures form only fragile films. This is the additional evidence of poor compatibility of components in this system. Thermo-mechanical characteristics of MC zosterine and HEC-zosterine films evidence the presence of only one glass-transition process for mixtures of all studied contents. The temperature of this transition decreases monotonously with the growth of zosterine concentration that points to high degree of components’ dispersion in these mixtures.
P-122 DYNAMIC SURFACE PROPERTIES OF MIXED LYSOZYME/STRONG DENATURANTS/ POLYELECTROLYTE
SOLUTIONS
O.Yu. Milyaeva, B.A. Noskov Department of Colloid Chemistry, St. Petersburg State University, St. Petersburg, Russia
The protein adsorption at liquid – fluid interfaces is an important step in various technological and biotechnological processes [1]. At the same time, the degree of destruction of the protein’s tertiary and secondary structures in the course of adsorption still remains to be elucidated [2, 3]. It has been shown recently that the unfolding of globular proteins in the surface layer results in a local maximum of the dilational dynamic surface elasticity [3, 4]. The surface elasticity of solutions of bovine serum albumin (BSA) and beta-lactoglobulin (BLG) in presence of strong denaturants such as urea and guanidinium chloride (GuHCl) increases monotonically with the surface age if the denaturant concentration does not exceed a certain critical value. At higher concentrations of the denaturant the dependence becomes non-monotonicand the surface elasticity approaches low values close to equilibrium indicating the formation of loops and tails in the surface layer. The lysozyme molecules are more stable at the interface as compared to BLG and BSA, and the local maximum of the surface elasticity appears at higher concentrations of the denaturants than in the case of BSA and BLG solutions. The addition of polyelectrolytes to protein/GuHCl solutions can result to further changes of the kinetic dependencies of the dynamic surface elasticity if the protein and polyelectrolyte are oppositely charged. The influence of polyelectrolyte is quite week for the mixed polydiallyldimetylammoniumchloride (PDADMAC) and BSA/GuHCl solutions at pH 7 but very strong in the case of mixed sodium polystyrenesulfonate (PSS) and lysozyme/GuHCl solutions also at pH 7. In the latter case the kinetic dependencies of the dynamic surface elasticity indicate the complete loss of the lysozyme’s tertiary structure in the surface layer if the PSS concentration exceeds 0.1 g/l. This strong synergistic effect was observed only for the unfolding of lysozyme globules in the surface layer under the influence of PSS/GuHCl mixture and probably elucidates the contribution of electrostatic interactions between the protein and denaturant in the course of globule unfolding. If GuHCl is replaced by urea this effect disappears and the kinetic dependencies of the surface elasticity become monotonic if the PSS concentration is higher than 0.01 g/l. Another prerequisite of the synergistic effect is probably the flexibility of the polyelectrolyte chain facilitating the interaction with the oppositely charged amino acid residues of the partly destroyed protein globule. [1] Kizilay E.; Kayitmazer A.B.; Dubin P.L., Adv. Colloid Interface Sci. 2011, 167, 24-37. [2] Wierenga P.A.; Gruppen H., Curr. Opin. Colloid Interface Sci. 2010, 15, 365-373. [3] Noskov B.A. Adv. Colloid Interface Sci. 2014, 206, 222-238. [4] Noskov B.A.; Mikhailovskaya A.A.; Lin S.-Y.; Loglio G.; Miller R., Langmuir, 2010, 26, 17225-17231. Acknowledgements: The work was financially supported by the Russian Foundation of Basic Research (RFFI No. 14-03-00670_a), the National Science Counsel of Taiwan (joint RFFI-NSC project No. 12-03-92004-ННС_а) and St.Petersburg State University (project No 12.38.241.2014).
P-123 LANGMUIR MONOLAYERS AND LANGMUIR-BLODGETT FILMS BASED ON POLYMIDE POLYMER BRUSHES CONTAINING
MAGNETITE NANOPARTICLES
O.A. Inozemtseva1, S.A. Klimova1, S.V. German1, D.A. Gorin1, D.M. Ilgach2, T.K. Meleshko2, A.V. Yakimansky2
1 - Saratov State University (SSU), Saratov, Russia 2 - Institute of Macromolecular Compounds Russian Academy of Science (IMC RAS), Saint-Petersburg, Russia
Molecular brushes are composed of a flexible backbone and densely grafted side chains [1]. The strong interaction of hydrophobic polymethylmethacrylate (PMMA) side chains provides an opportunity of application of such regularly grafted polyimide copolymers for formation of monolayer at air water interface named Langmuir monolayer. In this work polyimide polymer brushes with different length of side chains were synthesized via “grafting from” technique using atom transfer radical polymerization [2]. The prepared hydrophobic magnetite nanoparticles with the average size 18 ± 2 nm were used for composite layer fabrication. Monolayers of the polyimide brushes with and without magnetite nanoparticles were formed at the air/water interface by spreading of polymer brush solution in organic solvent with or without magnetite nanoparticles onto water surface. The area-pressure isotherms of polymer brushes show the aliquot independence of limit area per molecule values. It was established that the value of limit area per molecule increased with increasing length of side chains of the polymer brushes. Langmuir monolayers based on the polyimide polymer brushes with magnetite nanoparticles were formed at the air/water interface and transferred on substrate at various values of surface pressure (0.5 mN/m, 10 mN/m and 25 mN/m). It was shown that the limit area per molecule increased with increasing concentration of magnetite nanoparticles in spreading polymer solution. This fact can prove incorporation of nanoparticles into brush monolayer. The morphology of polymer brush monolayers and nanocomposite monolayers with hydrophobic magnetite nanoparticles at the different surface pressure were investigated by atomic force microscopy. AFM investigation of these submonolayer surfaces demonstrated that their morphology is determined by the monolayer phase state, which depends on the surface pressure of the transferred monolayer. The roughness of films based on polymer brushes without nanoparticles grows with an increase in the surface pressure regardless of the side chain length of the polymer brush. It was established that an increase in the average surface roughness by a factor of 4-6, as compared to submonolayers of the pure polymer brushes, is typical for all samples containing magnetite nanoparticles as a result of incorporation of magnetite nanoparticles into the polymer brush submonolayers. It is important to note that an increase in the surface roughness with increasing concentration of magnetite nanoparticles is more pronounced for the polyimide brush with longer PMMA side chains, providing a higher adsorption capacity of the polymer layer for nanoparticles. The composite films were characterized by transmission electron microscope (TEM). The dependence of the distribution of magnetite nanoparticles in the composite film on polymer structure was established. As a result the polyimide brush films with or without magnetite nanoparticles were formed at the air-water surface. These nanocomposite films can be applied as scaffolds with remote control properties for tissue engineering. The reported study was partially supported by RFBR (grant 12-03-33088 mol_a_ved).
1. M. Zhang, T. Breiner, H. Mori, A. H. E. Muller, Polymer, 44, 1449–1458 (2003). 2. T. K. Meleshko, D. M. Il’gach, N. N. Bogorad, N. V. Kukarkina, E. N. Vlasova, A. V.
Dobrodumov, I. I. Malakhova, N. I. Gorshkov, V. D. Krasikov, A. V. Yakimansky, Polymer Science, Ser. B., 52, 589-599 (2010).
P-124 HIGH-TEMPERATURE NETWORK COPOLYMERS OBTAINED BY CO-CURING DICYANATES WITH ROLIVSANS (DIVINYLAROMATIC
ETHERS AND THERMOSENSITIVE (DI)METHACRYLATES)
B.A. Zaitsev, O.V. Sorochinskaya, L.G. Kleptsova, I.D. Shvabskaya Institute of Macromolecular Compounds RAS
The chemical transformations and structures of the conventional thermosetting polymers can be strongly altered to enhance temperature performance, processing ease and transparency, for example. Therefore it is very difficult to attain these properties in one material, especially if the target is the creation of high-temperature potting, casting and encapsulating compounds rather than polymer fibers, films, or coatings. Rolivsans (ROLs) and cyanate esters (CE) may be considered suitable candidates for attaining the above-mentioned combination of contradictory properties in polymer materials. They are relatively new classes of high-temperature thermosetting resins that bridge the gap in thermal performance between polyepoxides and thermosetting polyimides. Both cured ROLs and CE (polycyanurates) are crosslinked, aromatic/heterocyclic polymers that have a high heat deflection (HDT)/glass transition (Tg) temperatures, low dielectric constant, low moisture absorption, low shrinkage, and can withstand continuous exposure in air in the temperature range of 250-350°C without exhibiting a significant loss of structural integrity. ROLs are known to be low viscous solvent free multifunctional compositions containing (di)vinylaromatic ethers and thermosensitive methacrylates obtained by acid-catalyzed chemical transformations (“condensation”) of di-sec. fatty-aromatic diols, such as bis-[p-(1-hydroxyethyl)phenyl] ether, HO-(H3C)HC-Ph-O-Ph-CH(CH3)-OH, with methacrylic acid (MAA). The resin compositions contain both monomeric and oligomeric [1] phenyl ethers with p-vinylphenyl and thermosensitive methacrylate (-ArCH(CH3)-O-C(CH3)=CH2) end groups [2, 3]. The thermal cure of ROLs includes three dimensional bulk copolymerization of their unsaturated components and subsequent cationic intramolecular (poly)cyclization in the crosslinked polymer chains between pending reactive groups belonging to the neighboring units. As a result of these reactions, ROLs can be converted into crosslinked copolymers comprising units of bis-(p-vinylphenyl) ether, p-vinylphenoxy--tetralone and methacrylic anhydride [4, 5]. The copolymers do not reveal macroscopic phase separation. However they show spherical highly crosslinked domains of several tens to hundred nanometers surrounded by weakly crosslinked microscale layers as revealed by both transmission electron microscopy and small-angle X-ray scattering studies [6]. Chemical modification of the ROL copolymers by the incorporation of polyarylcyanurate moieties into their structure was the main object of this study. 4,4’-bisphenol-A dicyanate (BADCy) was introduced into the liquid ROLs at a level of 5-10 percent to develop a novel ROL/BADCy systems. Then the ROL and BADCy components were co-cured through the thermocatalytic ROL transformations and simultaneous and/or consecutive cyclotrimerization of the BADCy reactive cyanate groups in the presence of ~0.005 wt. % copper naphthenate. The cure reactions were investigated by DSC and IR spectroscopy. The gradual disappearance of -OCN peaks at 2236 and 2274 cm-1 and the appearances of absorptions at 1370 and 1567 cm-1 for triazine rings were observed after stepwise curing of the ROL/BADCy systems at different temperatures. Compared to the unmodified copolymers, the crosslinked ROL-BADCy copolymers comprising 5-10 wt. % polyarylcyanurate moieties showed the increase of dynamic Young’s modulus (E) from 2.75 to 3.73 GPa and much lower extent of thermo-oxidative degradation during 350C exposure in air. References [1] B.A. Zaitsev, R.F. Kiseleva, I. O. Gusarova. J. Polym. Sci., Part A: Polym. Chem. 1996, 34, 1165-1181. [2] B.A. Zaitsev, G.I. Khramova, I.D. Shvabskaya. Russian J. Appl. Chem. 2007, 80, 623-628. [3] B.A. Zaitsev, G.I. Khramova, T.S. Tsygankova. Russian J. Appl. Chem. 2003, 76, 634-638. [4] B.A. Zaitsev, I.D. Shvabskaya. Russian J. Appl. Chem. 2010, 83,1270-1280. [5] Zaitsev B.A., Shvabskaya I.D., Kleptsova L. G., Sorochinskaya O.V. Russian J. Appl. Chem. 2013, 86,1751-1759. [6] Bronnikov S. V., Zaitsev B. A. Sukhanova T. E. Russian J. Appl. Chem. 2004, 77, 613-617.
P-125 COMPUTER SIMULATION OF BIORESORBABLE NANOCOMPOSITES ON THE BASE OF CHITOSAN AND CHITIN FILLER
B.M. Okrugin1, M.Yu. Ilyash2, I.M. Neelov2,3
1 - SPb State University, St.Petersburg, Russia 2 - Institute of Macromolecular Compounds, St.Petersburg, Russia
3 - ITMO University, St.Petersburg, Russia [email protected]
In recent years new bioresorbable nanocomposites containing natural polysaccharides and, in particular, chitin and chitosan were elaborated. It was obtained that in these composites the interaction of chitosan chains with chitin nanofiller leads to additional orientations of the chitosan molecules. At the same time the mechanism of this orientation was not quite clear. To understand the molecular mechanism of the orientation, we carried out the energy minimization and molecular dynamic simulation of systems containing of one chitosan molecule on the surface of chitin nanocrystallite using OPLS and AMBER94 forcefields. Chitin nanocrystallite contained 16 chains of chitin (4 chains in each of the 4 layers) consisting of 8 monomers. The initial conformations of chitin chains in nanocrystal were taken from the crystal structure of a-chitin. Chitosan chain in this simulation also consisted of eight monomers which is close to the size of the chitin nanocrystallite studied. To understand the effect of the orientation of chitosan chains by chitin nanocrytallites we used different initial orientation angles (from 0 to 180 °) of chitosan chains relatively the chitin chains in chitin nanocrytalite, where the angle of 0 ° corresponds to the orientation of the chitosan chain parallel to chitin chains in the nanocrystallite, and the angle of 180 ° - antiparallel. It was obtained that the parallel orientation of the chitosan chains relatively the direction of chitin chains in nanocrystallites has minimal energy in comparison with energies of chitosan chain of other orientations. It means that chitin nanocrystalites could orient the chitosan molecules. We have shown that this result could be explained by greater number of favourable contacts between chitosan and chitin molecules in the case of their parallel orientation. This work was partially supported by RFBR grants 13-03-00524, 13-03-00728 and Government of Russian Federation grant 074-U01. Computing resources and software packages have been provided by Moscow State University (“Lomonosov” and “Chebyshev” supercomputers).
P-126 NEW COMPOSITE FILM COMPLEX MORPHOLOGY BASED ON POLYIMIDE PM AND HYBRID MQ-COPOLYMERS
L.A. Miagkova1, S.V. Kononova1, R.V. Kremnev1, N.V. Matyushina1, E.A. Tatarinova2,
V.E. Yudin1, N.N. Saprykina1, E.N. Popova1, I.V. Gofman1, G.A. Pankova1, N.N. Shevchenko1, V.M. Svetlichnyi1
1 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, St.Petersburg, Russia 2 - Enikolopov Institute of Synthetic Polymeric Materials, a foundation of the Russian Academy of Sciences, Moscow,
Russia [email protected]
Hybrid polymer composites based on polyimide prepolymer PM ( reaction product of pyromellitic acid dianhydride with 4,4-oxydianiline and MQ- copolymers ((PM : MQ) - composites ) were synthesized. MQ- copolymers {[(SiO2] n [SiO (OH) 1,5]m [(CH3)2(Ph) SiO0,5] k Q: M = 1:1} was obtained during the hydrolytic polycondensation process. By coating the joint solutions of the polyamide acid and MQ-copolymer in an amide solvent on the glass surface, with subsequent evaporation of the solvent and heat treatment to complete thermal imidization, were obtained solid , heat-resistant composite films PM : MQ 50:50 wt % : E = 1.0 GPa, br=51MPa, b=34%, Tg=3550C, τ5=5150C. A study was made of the structural features of composite films based on PM : MQ. SEM spectroscopy revealed that the hybrid films are morphologically complex system consisting of a extended matrix phase containing disperse silicon phase . The disperse phase is a globule enriched with organosilicon component, while the matrix is composed mainly from a polyimide. Composite film, characterized under cooled nitrogen adsorption in accordance with the theory of Brunauer , Emmett and Taylor, had a specific surface area from 0.45 to 0.55 m2 / g, pore volume of 0.001 to 0.002 cm3 / g with a broad size distribution from the pore radii available from 1.5 to 10 nm. It is shown that the formation of (PM : MQ) - composite decreases specific pore volume of the film compared to the film PM, prepared under similar conditions. In the study (PM : MQ) - composite films under pervaporation separation of a mixture of 5 wt .% toluene - 95 wt .% methanol permeability was 0.527 kg mkm/m2 h at a concentration of toluene in the permeate 68.22 wt. % , which corresponds to the separation factor 40.78 . The introduction of a 50 wt .% MQ- polyimide copolymer film in PM increases the permeability of toluene more than an order and about in 5.5 times increases the permeability to methanol, separated from the mixture with 5 wt . % toluene. Carryover effect part of the ability of toluene MQ- copolymer dissolved in toluene, ie a high level of affinity between them. Increase the transfer rate of methanol may be due to the effect of swelling in toluene composite areas containing high concentrations of silicon component, or with the effect of increasing the free volume due to the formation of the structure of "loose " in the morphology of the composite film. The study was supported by the Russian Foundation for Basic Research (grant No. 13-03-12111- ofi-m).
P-127 THERMALLY REARRANGED POLYMER AS PERSPECTIVE MEMBRANE MATERIAL IN ORGANIC SOLVENT PURIFICATION
A.Yu. Pulyalina1, K.Yu. Veremeychik1, M.Ya. Goikhman2, I.V. Podeshvo2, A.M. Toikka1,
G.A. Polotskaya2 1 - Saint-Petersburg State University, Department of Chemical Thermodynamics & Kinetics, Universitetskiy pr.26,
Saint-Petersburg, 198504, Russia 2 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr.31, Saint-Petersburg 199004,
Russia [email protected]
At present the most actual task in inductry is an active introduction of energy saving and ecologically safety technologies. Membrane technology is one of the most perspective and economically sound in sphere of the separation, purification and concentration of gases and liquids. At the optimal choice of the membrane material it is possible to reach a high degree of selectivity in separation of industrial important mixtures. Wide variety of membrane technology applications at limited assortment of commercial membranes promotes the development of novel membrane materials with improved transport properties. The task of the present work is the development of novel polymer membranes for purification of organic solvents. The objects of presence work is polybenzoxazinonimide (PBOI) obtained by thermal rearrangement of their hydrolytically stable prepolymer polyamic aside (PAC-PI). Recently thermal rearranged polymers are of intense interest because of thermally rearrangement usually leads to the formation of excessive free volume that plays a great role in mass transport through the membrane.
O
NH
HOOC
N
O
O
HOOC
O
NH
N
O
O
Benzoxazinone
Imide To characterize membranes the morphology of polymer films were investigated by scanning electron microscopy, the density was measured and packing density of macromolecules (free volume fraction) was calculated. The thermal stability of membranes was analyzed by thermogravimetric analysis, the study of mass transfer through the membrane was performed based on the sorption and diffusion parameters. It was established that PBOI membrane has a denser structure as compared with the prepolymer PAC-PI . Furthermore, PBOI is preferably permeable to water and inert to isopropanol. Transport properties of the membranes were studied in pervaporation experiments (permeation and evaporation through the membrane). PBOI membrane was highly effective in the dehydration of organic solvents and markedly more selective to water in comparison with prepolymer membranes Acknowledgement. The work was supported by Saint Petersburg State University (grant № 12.38.257.2014).
P-128 THE DEPENDENCE OF ACRYLIC POLYMERS SURFACE ACTIVITY IN AQUEOUS SOLUTIONS ON MOLECULAR MASS AND
MACROMOLECULES MICROSTRUCTURE
A.A. Logunova1, E.V. Sivtsov1, O.G. Yasnogorodskaya1, E.V. Chernikova2 1 - Plastics Technology Department, Saint-Petersburg State Institute of Technology, Russia 2 - Department of Chemistry, M.V.Lomonosov Moscow State University, Moscow, Russia
Polymeric surfactants are of great interest to use for many applications because of their unique features: (a) the very strong tendency to adsorb at phases interfaces, even at low concentrations and independently of such conditions as electrolyte concentration, temperature etc.; (b) the possibility to contain a long hydrophilic part (polyoxyethylene chain, for example) and to retain their surface activity unlike low molecular mass surfactants leaving the interface and losing surface activity if hydrophilic part grows too long. When surface activity of polymers are studied the following factors have to be considered: hydrophilic-hydrophobic balance, molecular mass, microstructure and macromolecular architecture of polymers, the presence of ionogenic groups ionized or capable of dissociation, the rate of ionization, the nature of counter-ions, flexibility of polymeric chains. The surface tension isotherms of poly(acylic acid) (PAA) and poly(acryl amide) (PAAm) aqueous solutions of the following values of the polymers molecular mass were obtained: PAA – 28000, 18000, 10000 and 4000 (Mn); PAAm – 96000, 51000, 44000 and 28000 (Mη). It was shown the surface activity of the polymers increases with their molecular mass growing. The influence of the microstructure of acrylic acid (AA) – n-butyl acrylate (BA) copolymers prepared by pseudoliving radical polymerization by the reversible addition–fragmentation chain transfer (RAFT) mechanism on their surface activity in aqueous solutions was studied. Random copolymers of AA and BA, synthesized by the RAFT mechanism, exhibit increased surface activity in comparison with the copolymers obtained by the conventional radical polymerization. The higher the content of “anchor” BA units, the greater the extent to which the copolymers decrease the surface tension of aqueous solutions. It was found that under equal other conditions, block copolymers of AA and BA exhibit higher surface activity than do random copolymers. This difference depends on the content of BA units, solution concentration, and chain flexibility. In dilute solutions, macromolecules occur in the adsorbed layer in the unrolled conformation, which causes strong effect of the microstructure on the surface tension and more complete participation of “anchor” BA. Adsorption of a separate unit is reversible and is characterized by a certain dynamic equilibrium specific for the given conditions. Because of the large number of anchor units, adsorption of the macromolecule as a whole is irreversible. Such dynamics affects considerably more strongly the state of random copolymers than the state of block copolymers, because it is hardly probable that desorption of a separate BA units in a block is accompanied by removal of the BA unit from the effective adsorption layer, as this unit is retained by the adjacent units. However, at random structure of the chain, when an BA unit is surrounded by sequences of AA units, this process is more probable. The mechanisms of adsorption of polymer macromolecules on the phase boundary, accounting for the difference in the behavior of the random and block copolymers, were suggested. The pH dependence of the surface tension of 1% solutions of random and block AA–BA copolymers was investigated. It was found the random and block copolymers behave differently. Ionization of carboxy groups of AA–BA copolymers leads to a decrease in their surface activity. At pH > 7, the random copolymers fully lose the surface activity, in contrast to the block copolymers preserving the capability for adsorption on the phase boundary. It is suggested to use the block copolymers synthesized by the RAFT procedure as surfactants whose performance weakly depends on pH of the medium.
P-129 DIELECTRIC PROPERTIES OF POLYETHELENE WITH DISPERSE FILLER OF BERGMEAL
Ju.K. Osina, M.E. Borisova
Saint-Petersburg State Polytechnical University, Polytechnical st. 29, Saint-Petersburg, 194251 Russia [email protected]
The present work reports results of an investigation of polyethelene PE high density with 2 vol.% of disperse filler on the bases bergmeal ( SiO2· nH2O). The charging Ich(t) and discharging Idis(t) currents were measured in temperature range 90 – 110oC. The dependences of Ich(t) for samples of PE with addition 2 % (SiO2·nH2O) into the polymer matrix are shown in Fig.1. The experimental curves Ich(t) were analyzed on bases physical model of structurally non-homogeneous dielectric or by parallel-series equivalent circuit (Foight circuit) with parameters, determined by equations rn=h/S; cn=0м/h; n= cn rn=0м/; ci= 0si/h; ri=n/ci=hi/0siS (1)
where cn – high frequency capacity, rn – total value of dielectric resistance, ϑi = ciri – relaxation time , i = 1, 2 …(n – 1). IF
ch.(t) - IF
tr.= IFtr.n
i=1 rn/ri exp(-t/i) IF
tr.=Up/rn (2) From curves Ich(t) were calculated the dielectric characteristics εʹ = f(ω), εʺ = f(ω), tgδ(ω), Za = f(ω) and Zc = f(ω) for different temperature. The dependences tgδ(ω) for PE +2% SiO2· nH2O are presented on Fig.2.
Fig.1 The charging current as function Fig.2 The frequency dependencies of tgδ (ω) of time From Fig.2 it is shown that with increasing temperature the curves tgδ(ω) shift to high frequency. The increasing of tgδ at low frequency may be due to Maxwell-Vagner polarization and conductivity which is dominant mechanism at low frequency and high temperature. It is necessary note that introduction of disperse filler (SiO2·nH2O) into polymer matrix (PE) increases the tgδ over a low frequency range (10-4 – 1 Hz). The observed law is connected with non-homogeneous structure of dielectric and peculiarities of molecular mobility of polymer chains.
P-130 COMPLEXES OF MULTI-WALLED CARBON NANOTUBES WITH N-ALKYLATED POLY(VINYL PYRIDINES)
A.V. Kubarkov, L.A. Mashtak, N.M. Roshchupkin, O.A. Pyshkina, V.G. Sergeyev
Department of Chemistry, M.V. Lomonosov Moscow State University [email protected]
Carbon nanotubes (CNT) are unique objects combining extraordinary electrochemical and optical properties and excellent mechanical strength. Processing and application of CNT is complicated due to their insolubility in all common solvents because of strong tendency to aggregation. Stability of nanotubes in solvents can be significantly improved by obtaining their complexes with lyophilic polymers based on non-covalent interactions between the polymer and nanotubes surface. In present investigation composites of multi-walled CNT with N-alkylated poly(4-vinylpyridines) (PVP) were prepared by ultrasonicating the components in aqueous media. Such complexes can be stabilized by Van der Waals forces along with hydrophobic and electrostatic interactions. In order to evaluate the contribution of different interactions in solubilization of CNT, the PVPs of different chemical structure were used such as N-ethylated PVPs and PVPs containing various ratios of ethyl- and dodecyl- substituents. It was found out that nanotubes can form stable aqueous dispersion in the presence of all studied PVPs. The maximum concentration of CNT in such dispersions is about 0.1%. However, further increase of CNT content results in precipitation of almost all amount of CNT. It can be concluded that polymer evenly distributed over the surface of nanotubes. If excessive CNT content is used, the amount of polymer become insufficient to cover single nanotubes, so aggregation of such complexes occurs. The degree of ethylated PVP quaternization is likely to have an influence on interaction of this polymer with nanotubes and surrounding aqueous media as well. However, the composition of soluble CNT-PVP complexes and maximum achievable concentration of CNT in solution were found to be almost independent upon the quaternization degree of ethylated PVP. Preapared CNT-PVP composites are found to be highly electrically conductive. Conductivity of CNT complexes with ethylated PVP is reaching 100 S/cm, which is higher by almost an order of magnitude in comparison with conductivity of pristine CNT. This can be explained by ordering of nanotubes within their complexes with PVP which favor the improvement of electron transport between single nanotubes. In order to investigate the influence of CNT chemical structure on the properties of resulting complexes, CNT were chemically modified by oxidation which resulted in formation of carboxylic groups on their surface. Complexes of PVPs with oxidized CNT were found to be soluble over the broader range of CNT contents as compared to complexes of non-modified CNT. This is because carboxylated nanotubes are less inclined to aggregation in aqueous solution and possesses higher dispersion stability. They also can interact electrostatically with alkylated PVPs. Obtained composites are promising for applications as electrically conducting transparent coatings and films, electrode materials and chemical sensors. This work was carried out with financial support from Russian Basic Research Fund (№ 13-03-00605-a).
P-131 THERMAL STABILIZATION OF POLYACRYLONITRILE/MULTIWALL CARBON NANOTUBES
COMPOSITE FILMS
G.S. Chebotaeva, N.A. Gvozdik, A.K. Berkovich, V.G. Sergeyev Moscow State University [email protected]
Addition of multiwall carbon nanotubes (MWNTs) to polyacrylonitrile (PAN) precursors is known to improve mechanical properties of carbon fibers resulting from PAN thermal treatment, but little information is available on details of thermally induced stabilization of PAN/MWNT nanocomposites. This work aimed to analyze structure and properties of PAN/MWNT composite films based on PAN homopolymer, poly(acrylonitrile-co-methyl acrylate) (P(AN–MA)), poly(acrylonitrile-co-itaconic acid) (P(AN–IA)) and poly(acrylonitrile-co-methyl acrylate-co-itaconic acid) (P(AN–MA–IA)) copolymers and to investigate the role of MWNTs as reinforcing phase which can trigger stabilization of PAN. PAN/MWNT composite and PAN samples were prepared from dimethyl sulfoxide solutions by solution cast technique. Simultaneous thermogravimetric analysis, infrared spectroscopy of solid and gaseous products, and scanning electron microscopy studies were applied to elucidate the effect of MWNT addition on structure and thermal properties of the resulting composite material as well as the stabilization mechanism. It was found out that addition of MWNTs significantly changed the structure of composites produced from PAN homopolymer as well as P(AN–MA) and P(AN–IA) copolymers, resulting in decrease of the specific heat of stabilization process. Structure of the parent nanocomposites led to less local overheating and, therefore, to higher product yield and more perfect product structure. FTIR studies revealed that the products prepared in the presence and in the absence of MWNTs were different, other thermal processing conditions being the same. Thermal stabilization of the films containing MWNTs and the product structure were studied by means of DSC and FTIR in air and under argon atmosphere; no significant difference was found in temperature onset and specific heat of stabilization, and the products structure was similar. Under inert atmosphere oxidation was obviously impossible; hence, similarity of the above-mentioned process features proved that MWNTs seemingly hindered the oxidation reaction in the presence of oxygen. Furthermore, the approach applied to introduce MWNTs to the composite was crucial due to different filler distribution. For instance, properties of the reference composite samples prepared by simply adding MWNTs to PAN solution were similar to those of the material prepared without MWNTs. To conclude, MWNTs significantly influenced on the matrix structure resulting in unique properties of MWNT/polymer-based composites.
P-132 DISPERSION OF CARBON NANOTUBES IN AQUEOUS MEDIUM VIA POLYMER-WRAPPING
E. Karpushkin, A. Kozyr, A. Berkovich, V. Sergeyev
Moscow State University, Moscow, Russia [email protected]
Due to the unique structure, carbon nanotubes CNTs show up remarkable thermal stability, mechanical and conductive properties and are therefore applied in a vast range of high technology applications. For a number of reasons, the nanotubes are combined with industrial polymers to give composites differing in CNTs load as well as their distribution and orientation. Most often, even distribution of CNTs in the polymer matrix is desired. Solution technologies of CNTs dispersion are advantageous in terms of energy cost and equipment simplicity. Of the several methods of CNTs solubilization developed and studied in recent decades, noncovalent modification of CNTs through polymer wrapping or surfactant adsorption seem the most promising, as they preserve electronic and mechanical properties of pristine CNTs. Efficiency and kinetics of CNTs dispersion via polymer wrapping are determined by the nanotubes length and aspect ratio, the solvent nature as well as nature and concentration of the wrapping polymer. The process conditions (temperature, ultrasonication, mixing order, and stirring intensity) are also important. Despite a number of reports on CNTs dispersion via wrapping with polymer, no systematic generalization has been suggested so far to predict the dispersion efficiency and to optimize the process conditions. In order to partially fill in the gap, in this work we investigated dispersion of multiwalled CNTs in aqueous medium by treatment with poly-N-vinylpyrrolidone. In particular, the effects of polymer concentration and molecular weight, polymer-to-nanotubes ratio and mixing time were studied. The results contribute to development of the general model to explain the influence of various factors onto the dispersion process features and properties of the final products.
P-133 PREPARATION AND CHARACTERIZATION OF NAFION MEMBRANES MODIFIED WITH CARBON NANOTUBES
M.V. Artemov, E.A. Karpushkin, V.G. Sergeev
Lomonosov Moscow State University, Moscow, Russia [email protected]
Nafion is among the most widely used materials to prepare solid polymer electrolyte membrane for membrane fuel cells and redox flow batteries. Unique structure of Nafion leads to its excellent thermal and chemical stability as well as reasonably high proton conductivity. The main drawbacks of Nafion membranes are relatively high permeability towards the reactive species other than protons (methanol and oxygen in the case of fuel cells and vanadium ions in the case of redox flow batteries) and insufficient stability towards free radicals. Those drawbacks significantly decrease the devices efficiency and shorten their lifespan. Reported efforts to modify Nafion so that its properties are more thermally stable include membrane modification with metals, clays, silicon dioxide, inorganic salts, and polyoxometalates. Some success has been achieved but there is little data on long term stability under operating conditions. We report on preparation and properties of Nafion membranes modified with carbon nanotubes (CNT). Nafion-CNT composites were prepared by dispersing various amounts of CNT in Nafion solution followed by membrane casting. Besides other factors, properties of the final membrane are determined by structure of the casting solution. In particular, even distribution of CNT is usually desired. In order to investigate the interactions in CNT–Nafion mixed dispersions, we tested their rheological properties. The prepared membranes were characterized by their vanadium species permeability, proton conductivity, and thermal stability; those parameters were compared with corresponding properties of the pristine Nafion membrane. Effect of the preparation conditions is discussed.
P-134 STERIC STABILIZATION OF CEMENT DISPERSIONS BY CARBOXYL CONTAINING POLYMERIC SURFACTANTS
E.S. Ogorodnikova, V.D. Rodinova, A.I. Gostev, E.V. Sivtsov
Plastics Technology Department, Saint-Petersburg State Institute of Technology, Russia [email protected]
Nowadays in the industry of construction cement mixtures the special additives called super- or hyper plasticizer are of great interest both from the practical and fundamental points of view. These are the substances (often polymers or oligomers) increasing mobility of cement mixtures at the same or even a smaller amount of water. Use of such additives multifunctional: they make possible to increase density and durability of concrete due to reduction of an amount of water in mixture up to 30%, to keep its high mobility for a long time and to obtain concrete with low shrinkage and high strength. The idea of use carboxyl containing polymers as plasticizers is based on their ability to adsorb on a surface of cement grains creating a bulk protective layer around them and providing high stability of such colloid system consisting of cement particles dispergated in water. The polymers with long poly(ethylen glycole) (PEG) side groups distributed along the main chain have ideal structure for this purpose. Uniqueness of such polymers is that long PEG radicals provide very effective steric stabilization of dispersions instead of strictly limited electrostatic one, being enough hydrophilic to provide to the polymers solubility in water. In this work the described structure was obtained by radical copolymerization of acrylic acid (AA) and methoxy poly(ethylene glycol) methacrylate (MPEGMA). AA units are "anchor"-units providing adsorption of the polymer on cement particles, and MPEGMA units form "hair"-layer around the particles. Solubility of poly(AA-MPEGMA) depends on monomer structure (PEG radical length), temperature and molecular mass of the polymer. The monomer composition, temperature interval of use of the polymers as additives are quite defined. Therefore the only parameter regulating solubility of the polymers is molecular mass. To solve a complex problem of molecular mass regulation of the polymers and carrying out the polymerization in water (because of ecological positive orientation and easy heat release) poly(AA-MPEGMA) was synthesized in water solutions in the presence of copper (II) ions which cause termination of material chains by disproportionation of growing radicals and decrease polymer molecular mass. Depending on concentration of the ions it is possible to regulate molecular mass in a wide range – from several thousand to hundred thousands. In the analysis of relative activities of monomers it was established that AA is more active than MPEGMA. To improve compositional homogeneity of the copolymers the compensation way of polymerization (gradual dosing of more active monomer during the reaction) was used. The mechanism of steric stabilization was estimated using building of adsorption layers models by the computer modeling in real scale of possible structures. It was established the protective PEG layer around of cement particles provides such colloidal systems with aggregate stability and, that is extremely important, not interfering in cement hydration. The dependence of mobility of water-cement mixture on monomer composition of poly(AA-MPEGMA), on their molecular mass, the concentration of the polymer in the mixture, quality of cement is investigated. Dynamics of mixtures mobility change after their preparation was studied. For practical reasons it is considered that optimum time of preservation of mixture mobility is about 3 hours. The aim of the study was to find a polymer providing high mobility of mixtures during this time and not causing any decrease of final durability of a cement stone. It was shown the effectiveness of poly(AA-MPEGMA) as a plasticizer depends on quality of cement and the content of calcium hydroxide in it which forms insoluble salts with carboxyl groups. A way to improve aggregate stability of such colloid is to protect carboxyl groups of polymer by complexation with a suitable compound.
P-135 POLYMER NETWORKS MOLECULARLY IMPRINTED WITH BIOLOGICALLY ACTIVE SUBSTANCES
I.V. Polyakova, N.M. Ezhova, A.P. Leshchinskaya, I.S. Garkushina, A.R. Groshikova,
O.A. Pisarev, E.F. Panarin Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia
Molecular imprinting is a technique for creating affine recognition sites for an aim analyte in a synthetic polymer. In our work generally, molecular imprinted polymers (MIPs) were prepared via bulk polymerization by non-covalent method in which molecules of functional monomer assemble around aim templates by non-covalent interactions to form the recognition sites after co-polymerization with crosslinker and removal of the imprint molecules from the polymeric matrices. L-lysine (lys), erythromycin (erm), uric acid (ua) and cholesterol (ch) have been used as templates (T) to prepare imprinted polymers lysMIP, ermMIP, uaMIP and chMIP, correspondently. Methacrylic acid (MMA) and hydroxyethyleneglycol methacrylate (HEMA) were used as functional monomers (M) and ethyleneglycol dimethylacrylate (EGDMA) was used as a crosslinker (X) to prepare the MIPs. The major problem encountered in the synthesis of MIPs by this method was that the binding sites on the MIPs are usually heterogeneous. In other words, several different types of binding sites, having significantly or very different association constants coexist on the MIP surface. To improve the binding performance of the MIPs and their surface homogeneity and to shift toward higher values the energy of the different types of sites, the synthesis method was optimized. To optimize physicochemical properties of the polymer networks, the effect of different the X/M ratio both on the polymers structural stability in wide the pH range and on the electrochemical properties was studied. Optimization also included an increase of the concentration of template-functional complexes in prepolymerization mixtures. Series of MIPs were obtained with the different mol % contents of the templates in polymerization bulk. The effect of T/M ratio on specific and non-specific selective binding T with the correspondent MIP was studied at equilibrium sorption under varying pH and ionic strength in the sorption system. The main sorption parameters were compared with those obtained on the reference non-imprinted polymers (NIP). This allowed investigating the nature of intermolecular interaction in the studied sorption systems and estimating the contribution of specific and non-specific binding into the sorption selectivity. The influence of recognition conditions on the selectivity of the MIPs demonstrated that hydrogen bonding between substrates and the binding sites played an important role. Simultaneously, there had place the increase of the entropy term of the Gibbs free energy of adsorption due to disordering surface layer of solvent molecules when template distributed on the affinity binding site. Study of the degree of the binding affinity between the aim substances and the correspondent MIPs helped to find the experimental sorption conditions for shifting the distribution energies toward higher affinity sites and find the mobile-phase composition to improve peak shape on the MIPs.
P-136 IMPACT OF POLYHEDRAL OLIGOMER SILSESQUIOXANE NANOPARTICLES INTRODUCTION ONTO STRUCTURE AND
MORPHOLOGY OF NEW POLYAMIDOIMIDE NANOCOMPOSITES
A.Ya. Volkov, M.E. Vylegzhanina, L.I. Subbotina, V.M. Svetlichnyi, T.E. Sukhanova Institute of Macromolecular Compounds RAS, Saint-Petersburg, Russia
Recently, much attention is paid to organic silicon compounds - polyhedral oligomer silsesquioxane (POSS) with general formula (RSiO1,5)n, where R is an organic radical. Interest in these compounds is due to silsesquioxane skeleton silica gel containing the organic frames, preventing aggregation of nanoparticles and the ability of covalent binding to the matrix polymer. The introduction of POSS and its derivatives into polymer materials results in significant changes in their physical properties [1]. The aim of our work is the study of influence of Glycidylisobutyl POSS (С34Н74О14Si8) introduction – by blending or covalent binding to polymer, on structure and morphology of nanocomposites based on polyamide imide (PAI) matrix with different content of POSS nanoparticles. Figure 1(a) shows the diffraction patterns of neat PAI film (curve 1), initial POSS sample (curve 2) and the composite film of PAI with covalently bound 9 wt. % POSS (curve 3), which contained glycidyl groups. PAI film (curve 1) exhibits two diffuse reflections with maxima at 2θ = 13.5 and 15.5°. Under polarizing microscope, a glow indicating that the PAI film has mesomorphic structure is detected. On the other hand, POSS sample (curve 2) is characterized by a large number of reflections, that is, POSS is a highly crystalline substance. The diffraction pattern of the composite film of PAI with covalently bound 9 wt.% POSS (curve 3) again shown two diffuse halo, typical for mesomorphic phase, that testify to the homogenous (nanoscale) distribution of POSS in the polymer matrix. AFM data demonstrated the considerable difference in surface morphology and roughness (Ra from 2.9 nm till 22.2. nm) of the neat PAI and PAI-POSS composite samples prepared by blending (Fig. 1(c)) and the POSS covalently bounded to PAI polymer (Fig. 1(d)) as compared with the neat PAI matrix (Fig. 1(b)). Consequently, the introduction of POSS nanoparticles into PAI matrix by the covalent bonding results in the exfoliation of nanoparticles within the polymer and formation of the large-scale domain morphology.
Figure 1. WAXD diffraction patterns (a) of neat PAI (1), initial POSS (2) and PAI+9 wt. % POSS composite film (3); AFM images topography of neat PAI film (b), composite film of blend PAI
with 10 wt. % POSS (с), composite film of PAI+9 wt.% POSS (d).
[1]. V. M. Svetlichnyi, K. A. Romashkova, L. I. Subbotina, V. E. Yudin, E. V. Popova, I. V. Gofman, T. E. Sukhanova, E. N. Vlasova, and N. V. Afanas’eva. Nanocomposites Based on Polyamido Imide and Cube-Octameric Silsesquioxane // Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 3, pp. 415−422.
a b c d
P-137 HIGH TEMPERATURE CROSSLINKED COPOLYMERS OBTAINED BY CO-CURING (DI)VINYLAROMATIC ETHERS,
THERMOSENSITIVE METHACRYLATES, AND EPOXIES
I.D. Shvabskaya, B.A. Zaitsev, L.G. Kleptsova, O.V. Sorochinskaya Institute of Macromolecular Compounds of Russian Academy of Sciences, St.Petersburg, Russia
Essential distinctions in structure and properties of highly crosslinked microgel particles and surrounding defective polymer interlayer with lower crosslink density are a dramatic consequence of microheterogeneity of network polymers obtained by three-dimensional radical polymerization of dimethacrylates and/or other (poly)unsaturated compounds [1]. New approach for enhancing the interlinking of these microgels has been developed by example of the rolivsan’s chemical transformations [2,3]. Rolivsans (ROLs) are known to be low viscous solvent free multifunctional thermosetting resins containing (di)vinylaromatic ethers and thermosensitive methacrylates [4]. The thermal cure of ROLs results in the structures shown on the scheme. As to their morphology, the spherical highly cross-linked microgels with anhydride groups are uni-formly dispersed in the continuous microphase (the surroundings) comprising a
lower crosslinked polymer material. In the processes of the ROLs’ crosslinking and microsyneresis the surrounding area are enriched with low or nonreactive compounds (impurities) forced out from the polymerization sites. It
follows that different macroscopic properties of the cured ROLs and other thermosets are controlled by these external loose polymer microlayers playing the role of a poor binder interlinking the microgel fillers. According to the proposed method [2,3] common epoxy resins, specifically bisphenol A diglycidyl ether (DGEBA) and resorcinol-based epoxy resins (RER) as the targeted functionalized admixtures (1-10% wt.%) were solved in ROLs before the thermal curing. Incapable of radical crosslinking and the microgels formation at the initial stage of curing (140-180C), epoxies force out into the surrounding area (microlayers) reacting with the anhydride groups of the microgels at the post-cure stage (200-250C). ROL-Epoxy resins, wt.% Flexural strength (F
tC), MPa DMA, storage modulus (E’tC), GPa Epoxy Content 20 250 300 320 25 250 300 350 DGEBA 0 100 50 25 15 3.0 1.0 0.7 0.5 DGEBA 3-5 65 50 45 40 3.5 1.8 1.5 1.1 RER 5-10 65 45 45 45 - - - -
Numerous experiments following in this approach to the ROL chemical modification were carried out using dynamic mechanical analysis (DMA) at a frequency of 1 Hz (Table) and three point bending test (F
tC) for clear castings and laminates (Fig.1). The data obtained clearly show that new method for enhancing the interlinking of microgels in the network polymers operating with small amount of epoxies results in the nonadditive increase in heat resistance and strength (at elevated temperatures) of modified thermosetting resins and composites based on them.
References [1] Korolev G.V., Mogilevich M.M., Golikov I.V. Setchatye poliakrilaty. Moscow: Khimiya, 1995. [2] Zaitsev, B.A. in Proceedings (Extended Materials of Plenary Lectures) of X Int. Conf. on Chemistry and Physical Chemistry of Oligomers. Volgograd, Moscow: 2009, pp. 134–161. [3] B.A. Zaitsev, I.D. Shvabskaya. Russian J. Appl. Chem. 2010, 83,1270-1280. [4] B.A. Zaitsev, G.I. Khramova, T.S. Tsygankova. Russian J. Appl. Chem. 2003, 76, 634-638.
0 100 200 300
200
400
600
800
1000 1
2
1. Cured Rol:DGEBA=95:5 (wt.%)
2. Cured Neat Rol
F,
MPa
ToC
Fig. 1. Flexural strength (F) vs temperature
for the ROL glassfiber cloth laminates
Anhydride functionalized rolivsan
highly crosslinked copolymers (nanosized
domains or microgel particles)
Anhydride functionalized rolivsan
highly crosslinked copolymers (nanosized
domains or microgel particles)
Interlayer comprising:(a) defective polymer
network with impurities,
(b) additional epoxy chaines (bridges)
O
O OOO
O O
O O OO
.... ...
...... .
Fragment of microgel particle
P-138 STRUCTURE AND PROPERTIES OF ORIENTED TAPES PREPARED VIA SOLID-STATE PROCESSING OF A NASCENT
ULTRAHIGH MOLECULAR WEIGHT POLYETHYLENE REACTOR POWDER
E.K. Golubev1, A.N. Ozerin1, A.S. Kechkyan1, T.S. Kurkin1, V.A. Aulov1, I.O. Kuchkina1,
S.S. Ivanchev2, N.I. Ivancheva2, A.M. Martyanov3 1 - Enikolopov Institute of Synthetic Polymer Materials , RAS
2 - Boreskov Institute of Catalysis (St. Petersburg Branch), RAS 3 - Krasnoyarsk Chemical Company, Ltd
It is well known that both individual single crystals of polyethylene (PE) with a thickness of a few tens of nanometers and macroscopic single crystal mats formed from them readily undergo plastic deformation below their melting point. However, the technological implementation of the continuous production of high strength high modulus PE from single crystals or single crystal mats is hardly possible, because they can be obtained only through slow crystallization of the polymer from very dilute solutions. At the same time, if ultrahigh molecular weight (UHMW) PE is synthesized in the suspension mode with the use of specific catalysts, then, in some cases, it is possible to obtain nascent reactor powders with a morphology close to that of PE single crystal mats. So, the implementation of the continuous method of solid-state processing of high-strength and high-modulus oriented material become feasible. The aim of this study is to determine correlations between the molecular mass of the nascent UHMW PE reactor powder synthesized with the postmetallocene catalyst of the special structure and the specific features of plastic deformation during the orientational drawing of the compacted and monolithized material in the form of film tapes. Primarily, the investigation was arranged on the materials processed under laboratory conditions. After that, the comparative investigation was performed for the oriented tapes processed under continuous mode of deformation at the temperatures below the melting point of UHMW PE. The samples were characterized by WAXS, SAXS, SEM methods and mechanical testing. It was found that the bis{2-[(4-allyloxyphenylimino)methyl]-6-cumylphenoxy}TiCl2 catalytic complex [1] is optimum with respect to some criteria for solving the formulated problems. In the range 2 × 106 – 7 × 106, molecular mass was controlled via a change in the polymerization conditions. A big statistics on the UHMW PE reactor powders synthesized (more than 300 batches) made it possible to find the molecular mass 4.5 × 106 – 5.0 × 106 and the bulk density 0.05 – 0.09 g/cm3 mostly suitable to achieve the highest values of mechanical characteristics. Under comparable conditions of orientation drawing, the highest values of strength (4.0 GPa) and the elastic modulus (130 GPa) were found for the samples with optimized molecular mass characteristics. For the oriented tapes processed under continuous mode of deformation, the detailed structure investigation was performed for the transition deformation zone starting from weakly compacted reactor powder and ending with oriented reinforced tape. Thus, the postmetallocene catalyst mentioned above and proposed for the synthesis of nascent UHMW PE reactor powders provides not only a high yield of UHMW PE with a controllable molecular mass and morphology, but makes it possible to optimize the properties of the synthesized reactor powders in order to achieve maximally high mechanical characteristics of the oriented materials prepared on their basis via solid-state processing also. [1] Ozerin, A.N., Ivanchev, S.S., Chvalun, S.N., Aulov, V.A., Ivancheva, N.I., Bakeev, N.F. Polymer Sci., Ser. A, 2012, 54, No.12, 950-954; Patent RU 2459835.
P-139 SYNTHESIS OF AMPHIPHILIC POLYMERS OF PREDETERMINED MOLECULAR MASS IN RADICAL POLYMERIZATION IN THE
PRESENCE OF COPPER (II) AND CERIUM (IV) IONS
S.S. Borisyuk, E.V. Sivtsov, A.A. Logunova, A.I. Gostev Plastics Technology Department, Saint-Petersburg State Institute of Technology, Russia
Synthesis of well defined functional polymers with predetermined molecular mass characteristics influencing strongly on their topology, composition, functionality and suitability for a number of applications is in the centre of attention of many scientific laboratories. Ability to control of macromolecules structure is a question of great importance especially in the case of obtaining of polymeric surfactants. Nowadays the methods of controlled radical polymerization successfully solve this task but the conventional polymerization has a certain reserve due to some effective techniques and easy realization. In this study the influence of copper (II) and cerium (IV) ions on molecular mass characteristics of polymers in radical polymerization of acrylic acid (AA) and acryl amide (AAm) was investigated. Commonly using of copper and ions of the other transition metals is associated with atom-transfer radical polymerization or retardation and even inhibition in conventional radical polymerization. However as it will be shown below copper (II) and cerium (IV) ions can be effective molecular mass regulators in the fast polymerization of acrylic monomers. The dependence of polymers molecular masses on the presence of copper (II) ions was studied at the various copper concentrations: 0.01, 0.1 and 1 mass % (relative to the monomer mass). It was found molecular mass decreased with increasing of copper concentration without noticeable change in polymerization kinetics under conditions of the synthesis (20-25% water solutions, hydrogen peroxide as an initiator, 90°C). The following values of molecular mass were calculated for polymers synthesized in the absence of copper and in the presence of 0.01, 0.1, 1 % of copper sulphate: in polymerization of AA – 28000, 18000, 10000 and 4000 (Mn); in polymerization of Aam – 96000, 51000, 44000 and 28000 (Mη). This effect can be described by the scheme:
The scheme explains the decrease of molecular mass and the fact that any retardation was not observed in the systems containing copper (II) ions. Copper (I) ions forming in the chain termination reaction become a part of new redox initiation system so the kinetics chain does not terminate. Moreover generating of OH radicals catalyzed by copper (I) is probably faster than in reaction of thermal decomposition of hydrogen peroxide and copper ions can accelerate polymerization. A complication of kinetics study in this case consists in very high polymerization rate leading to almost complete monomer conversion for 10-20 minutes. The similar situation is observed in acrylic monomers polymerization in the presence of cerium (IV) ions. Obviously cerium (IV) causes chain termination and leads to decrease of polymer molecular mass according to the same scheme. But the probability of additional initiation by oxidation reactions of cerium (IV) with water or the other components of reaction system must be considered because of its high oxidation potential. Poly(AA) and poly(AAm) synthesized in this study have the amphiphilic nature due to the balance between hydrophobic main chain and hydrophilic side carboxyl or amide groups. The dependence of their surface activity in aqueous solutions on molecular mass was investigated.
CO R
CO R
+ Cu2+SO42-
CO R
CO R
+ Cu+HSO4-
Cu+HSO4-
+ H2O2 Cu2+SO42- + H2O + OH
+ CO R
nreinitiation
R = OH, NH2
P-140 PARAMETERIZATION OF ELECTROSTATIC INTERACTIONS IN MOLECULAR DYNAMICS SIMULATIONS OF THERMOPLASTIC
POLYIMIDES
V.M. Nazarychev1, S.V. Larin1, A.V. Yakimansky1, N.V. Lukasheva1, A.A. Gurtovenko1, I.V. Gofman1, V.E. Yudin1, V.M. Svetlichnyi1, A.V. Lyulin2, S.V. Lyulin1
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia 2 - Technische Universiteit Eindhoven, Eindhoven, The Netherlands
Thermoplastic polyimides (PIs) are extensively used in deferent areas of industry and technology as isolating coating, microelectronic boards, light and flexible materials in aerospace etc. [1]. Three thermoplastic polyimides which were synthesized in IMC RAS on the base of dianhydride R: 1,3-bis-(3´,4,-dicarboxyphenoxy)-bensene and three diamines BAPS: 4,4´-bis-(4´´-aminophenoxy)-diphenylsulfone, BAPB: 4,4´-bis-(4´´-aminophenoxy)-diphenyl, and BAPO: 4,4´-bis-(4´´-aminophenoxy)-diphenyloxide were selected as objects of present study. The dipole moment of R-BAPS repeat unit fragment including sulfone group (its chemical structure corresponds to diphenylsulfon, DPS) were calculated using three different quantum mechanical methods (Hartree-Fock, B3LYP, MP2), wide range of basis sets, and four population analysis methods (Mulliken, ChelpG, Chelp, Merz-Kollman). Four methods were chosen to parameterize electrostatic interaction (EI) for considered PIs in Gromos53a6 force field by comparing calculated dipole moment of DPS with experimental one. The equilibration procedure of PI samples and microseconds time-scale simulation in atomistic molecular dynamics (MD) was extendedly described in our previous works [2-5]. The validation of EI parameterization in MD was performed by quantitative comparison of simulated coefficients of thermal expansion (CTE) with experimental CTE values. It was shown that the best agreement was established when parameterization of EI was carried out by Hartree-Fock quantum mechanical method with the wave function basis set 6-31G* when partial charges were evaluated by Mulliken approach. Furthermore, in terms of proposed scheme this calculation method qualitatively predicts experimental ratio between glass transition temperatures Tg of all analyzed PIs (Tg
R-BAPS> TgR-BAPB > Tg
R-BAPO), which Tg were measured by three independent methods using differential scanning calorimetry, and as a maximum of loss modulus and loss tangent using dynamic mechanical analysis. All computer simulations have been carried out by the computational facilities of the Institute of Macromolecular Compounds, Russian Academy of Sciences and supercomputers “Chebyshev” and “Lomonosov” of the Lomonosov Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002 List of references [1] Bessonov, M. I.; Koton, V. V.; Kudryavtsev, M. M.; Laius, L. A. Polyimides: A Class of Heat-Resistant Polymers Consultants Bureau, New York, 1987. [2] Lyulin, S. V.; Gurtovenko, A. A.; Larin, S. V.; Nazarychev, V. M.; Lyulin, A. V. Macromolecules 2013, 46, 6357–6363. [3] Nazarychev, V. M.; Larin, S. V.; Lukasheva, N. V.; Glova, A. D.; Lyulin, S. V. Polym. Sci. Ser. A 2013, 55, 570–576. [4] Lyulin, S. V.; Larin, S. V.; Gurtovenko, A. A.; Nazarychev, V. M.; Falkovich, S. G.; Yudin, V. E.; Svetlichnyi, V. M.; Gofman, I. V.; Lyulin, A. V. Soft Matter 2014, 10, 1224. [5] Falkovich, S. G.; Lyulin, S. V.; Nazarychev, V. M.; Larin, S. V.; Gurtovenko, A. a.; Lukasheva, N. V.; Lyulin, A. V. J. Polym. Sci. Part B Polym. Phys. 2014, 52, 640–646.
P-141 COMPUTER SIMULATION OF PLASTICITY OF GLASSY POLYMETHYLENE
M.A. Mazo1, I.A. Strelnikov1, N.K. Balabaev2, E.F. Oleinik1, Al.Al. Berlin1
1 - Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygina 4, 119991, Moscow, Russia 2 - Institute of Mathematical Problems of Biology, Russian Academy of Sciences, 142290 Puschino, Russia
Molecular dynamics simulations are used to investigate of plastic deformation of amorphous polymethylene (PM). 32 computer samples consisted chains of different lengths with the average degree of polymerization 211 ± 16. All atoms were presented explicitly, and each sample consisted of 12288 –CH2– groups (36864 atoms in total). Each sample was subjected to an active isothermal uniaxial compression and tension at Tdef = 50 K (about 140 K lower the computed glass transition temperature Tg). Energy accumulation, non-affine displacements of carbon atoms and conformational rearrangements in chains were visualized and statistically analyzed as a function of macroscopic strain. It was found that:
1. At small strains εдеф ≤ 5% local segmental rearrangements involve to 16-20 –CH2- groups along PM chain (extending to about 20 Å) and domain up 12 Å around. At strains εдеф = 10-13% (near the yield strain) and εдеф = 30% (plastic flow) character of deformation does not change. Only number of segments included in plasticity increases with εdef, as well as area of intermolecular rearrangements increases up 18 Å. Also observed the cooperatives of the rearrangements at εдеф > 13%.
2. Conformational set of chains is changed insignificantly (not more than 0.6%) up to εdef = 30% (compression) and 40% (tension). The changes occurs mainly at εdef = 5-20%. Although conformational transitions contribute to the structural changes during the deformation the PM, they do not play a determining role even in the development of plastic flow.
3. Internal energy of glass is S-shaped with the highest rate of increase near the yield strain. Main part of the accumulated energy includes van-der-vaals interactions at tension. At compression the energy of rotational interactions is the largest, but the contribution of van-der-vaals and bond angles energy to the potential of energy close to one.
4. Local sites where high level of non-affine displacements were analyzed. It appears that such sites accumulate a noticeable excess volume. At growth of tensile strain a tendency to cavitation becomes evident, but it is no such tendency at compression.
P-142 MECHANICAL PROPERTIES OF THERMOPLASTIC POLYIMIDES: ATOMISTIC MOLECULAR DYNAMICS SIMULATIONS
V.M. Nazarychev1, S.V. Larin1, A.A. Gurtovenko1, S.G. Falkovich1, I.V. Gofman1, V.E. Yudin1,
V.M. Svetlichnyi1, A.V. Lyulin2, S.V. Lyulin1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
2 - Technische Universiteit Eindhoven, Eindhoven, The Netherlands [email protected]
Polyimides (PIs) are thermally stable polymers that are widely used in industrial applications due to their excellent thermophysical, electrical and mechanical properties [1]. Computer simulations based on atomistic chemically realistic models represent a powerful method to predict physical properties of new PIs before their synthesis. However, many problems related to simulation of mechanical properties of such materials are still open. In present study three thermoplastic polymides that are synthesized in IMC RAS on the base of dianhydride R: 1,3-bis-(3´,4,-dicarboxyphenoxy)-bensene and three diamines, namely BAPS: 4,4´-bis-(4´´-aminophenoxy)-diphenylsulfone, BAPB: 4,4´-bis-(4´´-aminophenoxy)-diphenyl, and BAPO: 4,4´-bis-(4´´-aminophenoxy)-diphenyloxide are considered. The atomistic molecular dynamics simulations are carried out in Gromacs package with Gromos53a6 force field successfully used previously [2-5] to simulate structural and thermal properties of PIs. Generation of equilibrated samples and parameterization of electrostatic interactions (EI) are described in details in our previous study [2-5]. Samples both with and without EI are cooled down after equilibration from 800 to 290K with different cooling velocity in range 1.5×1010÷1.5×1014 K/min. Mechanical properties are calculated by applying different deformation velocity (in range 6×102÷6×106 mm/min). It is found that Young’s modulus value shows dependence from cooling and deformation velocities close to logarithmic one. By applying uniaxial extension to bulk samples with constant deformation velocity 10 mm/min, experimental values of Young’s modulus are measured. Extrapolating of simulation results to experimental deformation velocity qualitatively reproduced experimental ratio between Young’s modulus of all examined PIs (ER-BAPS> ER-BAPB > ER-BAPO). Three-microseconds chemically realistic computer simulations are carried out using the computational facilities of Institute of Macromolecular Compounds, Russian Academy of Sciences and supercomputers “Chebyshev” and “Lomonosov” of the Lomonosov Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002 List of references: [1] Bessonov, M. I.; Koton, V. V.; Kudryavtsev, M. M.; Laius, L. A. Polyimides: A Class of Heat-Resistant Polymers Consultants Bureau, New York, 1987. [2] Lyulin, S. V.; Gurtovenko, A. A.; Larin, S. V.; Nazarychev, V. M.; Lyulin, A. V. Macromolecules 2013, 46, 6357–6363. [3] Nazarychev, V. M.; Larin, S. V.; Lukasheva, N. V.; Glova, A. D.; Lyulin, S. V. Polym. Sci. Ser. A 2013, 55, 570–576. [4] Lyulin, S. V.; Larin, S. V.; Gurtovenko, A. A.; Nazarychev, V. M.; Falkovich, S. G.; Yudin, V. E.; Svetlichnyi, V. M.; Gofman, I. V.; Lyulin, A. V. Soft Matter 2014, 10, 1224. [5] Falkovich, S. G.; Lyulin, S. V.; Nazarychev, V. M.; Larin, S. V.; Gurtovenko, A. a.; Lukasheva, N. V.; Lyulin, A. V. J. Polym. Sci. Part B Polym. Phys. 2014, 52, 640–646.
P-143 NUCLEATION OF CALCIUM PHOSPHATE REGULATED BY NATIVE BACTERIAL CELLULOSE. ASSESSING THE INFLUENCE OF
SOLVATION MODELS
D.A. Tolmachev, N.V. Lukasheva Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
The synthesis of composites designed for bone implants involves a soaking of polymer matrices in a solution of calcium phosphate (CP) ions (biomimetic route). The use of native BC as the polymer matrix is extremely attractive not only because of its remarkable structural and mechanical characteristics, but also due to its chemical purity and a very high biocompatibility. Formation of CP crystals from a solution on organic matrices depends on the presence of surface functional groups of the matrix (to cause a heterogeneous nucleation). To accelerate the mineralization process it is necessary an increased saturation of the surrounding solution or a pre-incubation in calcium-containing solutions (usually CaCl2). It is assumed that the hydroxyl groups of the cellulose having a strong negative dipole could chelate free Ca2+ cations in solution and form a coordinated bond thereby creating centers for the subsequent heterogeneous crystallization of CP minerals. Experimental studies are inconclusive with respect to the question of whether BC has an induction ability which is sufficient to provide the heterogeneous nucleation of CP. To answer this question the molecular dynamics (MD) simulations of the nanofibril of native BC, placed in CP and CaCl2 solutions were performed for the following concentrations: less, equal and above the limits of solubility. The influence of the solvation models (TIP3P, TIP4P and TIP4P-ew water models) on the structural characteristics of the simulated nanofibril and on the crystal nucleation process was assessed. It was found that the structural characteristics of the cellulose nanofibrils, in particular for the surface layer, exposed to water, are practically independent of the solvation models. At the same time, the structure and the size of the ionic clusters are different. Regardless of the used water models, the main conclusions are the same for all the considered systems. It was shown that the activity of the hydroxyl groups on the surface of BC fibrils is not sufficient to adsorb Ca2+ ions. The crystallization of CP can not take place on the surfaces of nanofibrils of native BC. Thus, the nucleation of CP crystals takes place initially in solution, and then, crystallites formed can be adsorbed on the surfaces of BC nanofibrils. The reported study was supported by RFBR, research project No. 14-03-32041
P-144 KINETIC AND DYNAMIC PARAMETERS OF SORPTION AND THE MAIN CHARACTERISTICS OF NANODIAMOND-INCLUDED
CELLULOSE MATRIX COMPOSITE
A.A. Sukhova, A.T. Melenevsky, E.N. Pavlova, E.S. Nikiforova, A.A. Demin Institute of Macromolecular compounds RAS, St.Petersburg, Russia
Creation of sorbent for purification of biologically active substances with the column method is interesting because of a low cost of associated equipment of the column method. Also it allows to receive individual substances from the mixture on an industrial scale. Because of the properties of composite sorbents sorption could be carry out with a high efficiency. Also in the structure of the composite sorbent could be impregnated sorbents that couldn`t be used directly for the sorption in column. The aims of the latest research are to obtain samples with optimum characteristics and to study the most important properties to predict the possibility of using a sorbent in practice. Composite sorbents were synthesized that combine the positive properties of the cellulose matrix and nanodiamonds. Nanodiamonds can be used as a sorbent-filler and carry out the sorption of proteins with high efficiency in the mode of column chromatography. The research allowed to determine the optimal ratio of cellulose-diacetate/nanodiamonds to obtain samples of sorbents with the best kinetic-dynamic characteristics.
P-145 GEL-FORMING DEXTRAN PHOSPHATES AS CARRIERS OF ANTINEOPLASTIC DRUG PROSPIDIUM CHLORIDE
T.L. Yurkshtovich, P.M. Bychkovsky, S.O. Solomevich, N.V. Golub, V.A. Alinovskaya,
R.I. Kosterova, A.B. Gaidalovich, P.Y. Mirchuk Belorussian State University, Research Institute for physical Chemical Problem, Minsk, Belarus
Among high-molecular compounds, which can be used as polymer-carriers of antineoplastic substances, biodegradable phosphates of polysaccharides in the form of micro- and nanogels have the widest application. They possess biocompatibility, possibility to create an overload effect of medical substance, sensitivity of their physical and chemical properties to the changes of environmental conditions and have no expressed side effects. The purpose of the study was to investigate the sorption of an antineoplastic drug prospidium chloride by modified gel-forming dextran with phosphate and carbamate groups (DFC), kinetics of prospidium chloride release from microparticles and antineoplastic activity in the in vitro and in vivo conditions. Macroporous samples of DFC were obtained by etherification of polysaccharides by orthophosphoric acid in presence of urea. Samples of DFC with degree of substitution on phosphate and carbamate groups 0,34 - 1,18 and 0,23 - 1,02, respectively, and swelling degree in the range of 10 – 222 g/g were investigated by IR-spectroscopy, 31P nuclear magnetic resonance spectroscopy, scanning electron microscopy, potentiometric titration, elemental and gravimetric analysis. Sorption of prospidinum (1-chloro-3-[12-(3-chloro-2-hydroxypropyl)-3,12-diaza-6,9-diazoniadispiro[5.2.59.26]hexadecan-3-yl]propan-2-ol dichloride) by DFC was studied depending on concentration of external solution, pH, sorption time, some physical and chemical parameters of hydrogels. In wide рН range 3,20 – 7,25 sorption capacity of DFC was determined not to change in relation to prospidinum. Time of equilibrium swelling does not exceed 15 min. Prospidinum was established to immobilize on hydrogels of DFC with ion exchange mechanism and the distributive mechanism. Possibility of formation of extra donor-acceptor bond between Prospidinum and the polymer-carrier was shown. Intensity of donor-acceptor bond at the fixed concentration of external solution increases with transition from less to more linked hydrogel. Release degree of prospidinum from the medical form of DFC depends on degree of polymer cross-linking and a mass ratio polymer – cytostatic. About 45 - 70% of prospidinum released from a carrier phase in the first stage. Further release of cytostatic provided by gel-sol transition. It can be confirmed by the fact of losing weight of hydrogel form of prospidinum in buffer solution. Values of constant of prospidinum release from a polymer phase are calculated. It was determined that the diffusion rate of antineoplasic agent isn’t affected only by swelling degree, but also by energy of interaction of drug with functional groups of macromolecules. Comparative study of antineoplastic activity of prospidium and its prolonged form in vivo was carried out on white outbred rats weighing 150-200 g on the models of sarcoma M-1, Janszen's sarcoma, Zaidel's ascitic hematoma. Results of medical-biological researches of the prolonged form of prospidium indicate increasing by 50% number of the cured animals in comparison with native substance solution.
P-146 CREATION OF THE SYSTEM OF TEMOZOLOMIDE ADDRESS DELIVERY
V.O. Mironchik, N.K. Yurkshtovich, T.L. Yurkshtovich, V.A. Alinovskaya, D.A. Adamchik,
N.V. Golub, A.B. Gaidalovich Belorussian State University, Research Institute for physical Chemical Problem, Minsk, Belarus
The purpose of this study was to develop the prolonged form of antineoplastic substance temozolomide, intended for the combined treatment of primary and metastatic tumors of a brain. Temozolomide (4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo[4.3.0]nona-2,7,9-triene-9-carboxamide) is one of the most effective drug for treatment of brain malignant tumors: glioblastomas, anaplastic astrocytomas, anaplastic oligodendrogliomas, low grade gliomas. Considerable disadvantages of temozolomide are toxicity, low water solubility, and instability of its water solutions in neutral and alkaline ranges of рН. With the purpose of removal of noted disadvantages and creation of address delivery system of antineoplastic agent to the place of tumor or its remains localization temozolomide, immobilized on biodegrading polymer is synthesized. Gel-forming dextran phosphates (DP) were used as polymer-carriers because of its biocompatibility, capability to create overload effect of medical substance and possession of its own antineoplastic activity. Gel-forming biodegradable samples of DP with degree of substitution on phosphate groups 0,1 ÷ 0,7 and swelling degree in the range of 8,0 – 37,2 g/g were obtained by etherification of dextran with weight-average molecular weight 60 kDa in the system Bu3PO4 – H3PO4 – P2O5. DP hydrogels were investigated by IR-spectroscopy, scanning electronic microscopy, potentiometric titration, element and gravimetric analysis. Sorption ability of the synthesized DP hydrogels with different cross-linking degree was investigated in relation to temozolomide depending on concentration of antineoplastic agent in water solutions, рН and time of sorption process. It was determined that sorption of temozolomide by DP is carried out by the distributive mechanism, and prolongation of cytostatic action of the drug is defined by the diffusion rate of temozolomide molecules, distributed in a spatial grid of DP hydrogels, to external solution. Under studied physical-chemical and sorption properties of DP hydrogels, an optimum mass ratio of temozolomide: hydrogel: water was determined to be 0,1-0,2: 0,8-0,9: 20-25, Comparative investigation of antineoplastic activity of DP, temozolomide and its prolonged form in vivo was carried out on the models of C6 glioma. Received results allow drawing a conclusion that all studied drugs with single peritumoral injection to the rats hypodermically intertwined with C6 glioma have expressed antineoplastic effect. Drug "Temodeks" was created and now it passes clinical tests on patients with primary tumors of a brain. Obtained data indicates increase in life expectancy and duration of the recurrence-free period, and also satisfactory tolerance and safety of the "Temodeks" as local chemotherapy drug for malignant tumors of a brain.
P-147 ETHER-CONTAINED FLUOROPOLYMERS AND ITS COMPOSITES
E.V. Savina, V.M. Rodin, V.I. Purtseladze, G.A. Emelyanov
FSUE "ISR" [email protected]
Last decades development of fluorinated copolymers is an important practical problem. It provides the ability to create flexible chemical-resistant materials. Most polar fluoroelastomers like a SKF-26 (VF-HFP copolymers) are efficiently cured by reagents acting on the main chain by an ionic mechanism [1]. Monomers with reactive functional groups can also be introduced into a polymer to make curing ability. In the presented work samples of copolymers of vinylidene fluoride, hexafluoropropylene and the functional monomer with an ether group were received. The properties of cured copolymers and curing mechanism involving the ether group were studied. It is shown that the main characteristics of studied samples do not concede the ones of nitrile-contain VF-HFP copolymers.
P-148 REVERSIBLE CHAIN TRANSFER IN RADICAL (CO)POLYMERIZATION OF N-VINYL SUCCINIMIDE
A.I. Gostev1, E.V. Sivtsov1, E.V. Parilova2, A.V. Dobrodumov2, E.V. Chernikova3
1 - Plastics Technology Department, Saint-Petersburg State Institute of Technology, Russia 2 - Institute of Macromolecular Compounds of the RAS, Saint-Petersburg, Russia
3 - Department of Chemistry, M.V.Lomonosov Moscow State University, Moscow, Russia [email protected]
(Co)polymers based on N-vinyl succinimide (VSI) cause intense interest due to possibility of application as hydrophilic non-toxic materials in medicine. Such copolymers can be easily modified by alkaline hydrolysis resulting in conversion of VSI units to the N-vinyl succinimidic acid (VSA) units with carboxylic groups attached to the main chain via –NH–C(O)–CH2–CH2– spacer permit to bind low molecular compounds including medicinal products to the polymers, leading to various advantages of such polymeric drug conjugates, for instance, their prolonged action in vivo. Obtaining soluble VSI homopolymer and copolymers with high composition homogeneity by polymerization in bulk is impossible using conventional radical polymerization because of the chain transfer reaction to VSI cycle methylene protons leading to cross-linked product and, in the case of copolymerization, a great difference of VSI and other vinyl monomers reactivity ratios. All these problems can be solved by using reversible chain transfer (or RAFT technique of radical polymerization). Poly(VSI) was synthesized using dibenzyl trithiocarbonate (BTC) as a RAFT agent. The presence of BTC redistributes the probabilities of elementary reactions of growing macroradicals: propagation, transfer to RAFT agent, transfer to polymer, termination. It minimizes the role of chain transfer to polymer and termination and leads to obtaining soluble non-crosslinked polymer with molecular mass well controlled, depending on the [monomer]/[BTC] ratio. The poly(VSI) samples were synthesized in this way with molecular masses (Mn) of 7000-48000. To find where CS3-group situates in polymer chains an additional experiment was realized. Poly(VSI) (1.3×10-4 mole/l) was heated in inert solvent (benzene) with excess of azobisisobutyronitrile (AIBN) as a source of radicals (3×10-1 mole/l) at 80°C during 24 h. If trithiocarbonate group is located in the middle of the polymeric chain after heating with AIBN in the absence of monomer the molecular mass of the polymer should decrease in half. If it is located on the tail, molecular mass should remain practically the same. In this case molecular mass of poly(VSI) samples changed correspondingly: from 7000 to 5300 and from 48000 to 40000. It evidences the chains grow with the different rates on both side of trithiocarbonate group. Chain length dependence on the elementary reactions rates, molecular mobility of propagating radicals, reactivity of the radicals have to be considered to explain the forming of such asymmetrical microstructure. The same is found in the case of copolymerization of VSI with the other monomers: 4-vinyl pyridine, butyl acrylate (BA) and vinyl acetate. Due to a deep difference in their reactivities in the presence of BTC copolymers of gradient chain microstructures are obtained. According to the ratio of the chains growing rates on both side of trithiocarbonate group symmetrical, asymmetrical and terminal microstructures can be formed with CS3-group situated correspondingly in the middle of chain, close to one of the ends of chain, at the end of chain. For example, in copolymerization of VSI with BA copolymers with gradient symmetrical microstructure (CS3-fragment is close to the middle of macromolecule, the composition of both the tails changes from practically homo-poly(VSI) at the trithiocarbonate group to the end enriched with BA units as a result of the reactivity ratios r(VSI)=0.11, r(BA)=2.54) are obtained. Thus compositionally homogeneous copolymers with well defined molecular mass, molecular mass distribution and microstructure can be synthesized at high conversions of monomers under the conditions of reversible chain transferring in the presence of BTC as a RAFT agent. This work was supported by Russian Foundation for Basic Researches (project No 14-03-00155)
P-149 POLYMER-SILICATE GELS AS ANTIFILTRATION BARRIERS PREVENTING PENETRATION OF LIQUID RADIOACTIVE WASTES
INTO GROUNDWATER
E.V. Sivtsov, V.N. Naumov, A.V. Polyakov, V.M. Tihomirov Colloid Chemistry Department, Saint-Petersburg State Institute of Technology, Russia
The storing of liquid radioactive wastes in special repositories results in formation of pollution sources which are very dangerous for groundwater and the ecosystem as a whole. Groundwater pollution can be prevented by means of engineered antifiltration barriers. This problem was investigated on the base of a model system consisting of silica sand as a high permeable substrate and sodium silicate solutions as an antifiltration impregnation composition because of their ability to form hydrogels under the conditions of acid catalysis. At the fist step the kinetics of gelation was studied. It was found that gelation time can be changed in the large range (from several minutes to 8 hours) by variation of the mixture components concentrations and the sodium silicate/acid catalyst ratio in particular. Using a certain ratio between the ingredients of the complex catalyst it is possible to achieve the stable gelation time (1 hour) at this catalyst composition that is suitable for practical purposes of the compositions. Moreover the temperature dependence of gelation time was observed in the gelation kinetics studies. A deep retardation of gelation occurs at the decrease in temperature from 30°C to 20°C (for example, from 160 to 265 minutes, ~ 65%), whereas the following decrease to 10°C extends gelation over 275 minutes (only ~ 6%). It is connected with molecular mobility dynamics in the gelating system. Modification of filtration ability of silica sand with the compositions described above occurs in the following stages: – wetting and impregnation of the substrate (it takes some minutes or hours depending on antifiltration solution composition), – gelation (some hours), and – forming of a common structure including the substrate and the silicate gel (months). The model systems with a low level of filtration ability obtained on the base of silica sand have some disadvantages which must be corrected for successful application of this compositions in natural conditions. First of all it is ablation of silicate gel from the substrate after a long but not sufficient period of successful work as an antifiltration barrier. At the second step modification of the antifiltration compositions by surfactants and polymer additives was investigated to prolong their functioning as barriers. Ionogenic and non-ionogenic surfactants, silicone emulsions, polymer latexes and polyacrylamide (PAA) and copolymers of acrylic acid and methoxy poly(ethylene glycol) methacrylate poly(AA-MPEGMA) were used as modification additives. Surfactants, emulsions and latexes can decrease permeability of substrate in some cases but in the certain moment a complete loss of antifiltration property occurs that is absolutely unacceptable for this application. Only PAA and poly(AA-MPEGMA) allow to achieve acceptable result – decrease water permeability of system and keep it for a long time (about one year under conditions of the experiment). In such polymer-silicate compositions the formation of complex network including the surface of substrate particles with macromolecules adsorbed on it and swollen polymer hydrogel was considered to explain the high stability of antifiltration property of the system. In the presence of sodium silicate pH>7 and PAA is partially undergone hydrolysis leading to formation of carboxyl groups in the polymer chains capable of absorbing to the surface of silica. As a result swollen PAA hydrogel is bound to the substrate, immobilized on it and can not be washed-out. In the case of poly(AA-MPEGMA) macromolecules contain "anchor"-units of AA to bind with silica, and in addition they have long hydrophilic poly(ethylene glycol) chains which fill up the volume between the substrate particles providing the system with permanent effective antifiltration function. It allows to recommend PAA and poly(AA-MPEGMA) as a perspective modification additive for antifiltration silicate gels.
P-150 SYNTHESIS AND PROPERTIES OF NANOCOMPOSITES BASED ON HETEROCYCLIC SOLUBLE POLYMERS AND
GLYCIDYLISOBUTYLSILSESQUIOXANE
L.I. Subbotina, A.L. Didenko, V.M. Svetlichnyi, V.E. Yudin, I.V. Gofman, E.N. Popova, N.V. Afanasieva
IMC RAS, St.-Petersburg, Russia [email protected]
Two amide solvent soluble polyimides, containing a side chain carboxyl group, were synthesized: PI-1 on the basis of dianhydride 1,3- bis(3',4 - dicarboxyphenoxy)benzene and 3,5- diaminobenzoic acid (DABA) and PI-2 on the basis of dianhydride 1,3-bis(3',4 - dicarboxyphenoxy)benzene with 1,4- bis(4' - aminophenoxy)diphenylsulfone , and DABA . Polymers, containing covalently attached nanoparticles, were obtained by using the synthesized PI-1, PI-2 and polyhedral oligomeric glycidylisobutylsilsesquioxane C34H74O14Si8 (POSS). Samples of polyimides, containing covalent attachment POSS nanoparticles from 3 to 10 wt.% for PI-1 and from 1.2 to 2.4 wt. % for PI-2, were obtained. It were also prepared the compositions (mixtures) of PI-2 contain POSS from 1.2 to 2.4 wt. % . The thermal stability (τ5 = 4230C) film samples of PI-1-POSS and physico-mechanical properties (E = 3.45 - 2.88 GPa ; σbr = 118 - 88 MPa; εbr = 36 - 10%) were evaluated. Increase of POSS in PI-1 leads to a reduction of dielectric constant from 4.6 to 4.0. A comparative study of thermal stability in an inert or in air of the synthesized PI-2 samples with covalently attached POSS and compositions obtained with a weight content equal POSS was conducted. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002
P-151 MOLECULAR DYNAMICS SIMULATION OF P3HT WITH ALL ANTI-CONFORMATION IN VACUO AND IN AMORPHOUS P3HT MEDIA
S.V. Larin1, N.I. Borzdoun2, I.V. Volgin2, V.M. Nazarychev1, S.V. Lyulin1
1 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russia 2 - St. Petersburg State University, Physical Faculty, St. Petersburg, Russia
Regioregular poly-3-hexylthiophene (P3HT) is a conjugated heterocyclic polymer that attracts great attention for application in organic electronics. P3HT-based composites filled with fullerenes and their derivatives are proved to be one of the most promising materials to produce organic photovoltaic cells. The efficiency of such cells strongly depends on the structure of polymer matrix. P3HT is semicrystalline polymer and usually its structure is described as combination of crystalline and amorphous domains. The most common representation of P3HT crystalline domain structure is layers of parallel elongated P3HT chain (all syn-conformation). However, there is evidence that P3HT chains can also form coiled spiral conformations (all anti-conformation) [1]. In the present study atomistic molecular dynamics simulation of regioregular P3HT helical structure was performed at room and higher temperatures (300 K and 425 K). Helical chain of P3HT in all anti-conformation was build with polymerization degree N = 70. Initial structure energy was minimized by means of molecular mechanics. Then simulations of this structure in vacuo were performed at two temperatures 300 K and 425 K to determine its stability and possible structure evolution. Also helical P3HT chain was simulated in amorphous polymer surrounding. To perform such simulation initial helical configuration of chain was surrounded by 27 shorter P3HT chains with polymerization degree N = 40. Structure evolution of helical structure and its influence of the nearest P3HT chains structure were investigated at both considered temperatures. The simulations have been performed using the computational facilities of the Institute of Macromolecular Compounds, Russian Academy of Sciences, and the Chebyshev and Lomonosov supercomputers at Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002 1. N. Kiriy, E. Jähne, H.-J. Adler, M. Schneider, A. Kiriy, G. Gorodyska, S. Minko, D. Jehnichen, P. Simon, A.A. Fokin, M. Stamm. Nano Lett. 2003. V. 3. P. 707-712.
P-152 COMPUTER SIMULATION OF EXTEM™ AND ULTEM™ POLYIMIDES USING GROMOS AND AMBER FORCE FIELDS
I.V. Volgin1, S.G. Falkovich2, S.V. Larin2, V.M. Nazarychev2, A.A. Gurtovenko2, A.V. Lyulin3,
S.V. Lyulin2 1 - St. Petersburg State University, Physical Faculty, St. Petersburg, Russia
2 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russia 3 - Technische Universiteit Eindhoven, Theory of Polymers and Soft Matter Group,Eindhoven, The Netherlands
In the present study the influence of chemical structure of thermoplastic polyimides (PIs) EXTEM™ and ULTEM™ on their structural and thermophysical properties is investigated by extensive computer simulation. The difference between monomer units of the polyimides considered is rather small: EXTEM™ has an additional sulphone group. However, their thermophysical properties are sufficiently different. Computer simulations were performed using atomistic models of polymers at the microsecond timescale. To examine the influence of model parameters on the simulation results two types of the force fields were used, i.e. Gromos53a6 and Amber99. To study the influence of partial charges parameterization on the simulation results the simulations were carried out with and without electrostatic interactions. Partial charges of polyimides were calculated using HF/6-31G* quantum-mechanical method for simulations with Gromos force field and AM1-BCC method with Amber one. The temperature dependence of density and coefficients of thermal expansion (CTE) for both ULTEM™ and EXTEM™ PIs were simulated at temperatures above and below the glass transition point Tg for two different cooling rates. The average values of density at room temperature and average CTE values below Tg were also calculated. Calculated CTE values are close to experimental ones for both force fields in case of simulations with electrostatic interactions. Simulations with Amber99 force field give a slightly better agreement with experimental data. We can conclude that electrostatic interactions between polar groups have sufficient influence on thermophysical properties of polymers and proper determination of thermophysical properties of PIs require simulations with electrostatic interactions taken into account. The simulations have been performed using the computational facilities of the Institute of Macromolecular Compounds, Russian Academy of Sciences, and the Chebyshev and Lomonosov supercomputers at Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002
P-153 INFLUENCE OF CARBON NANOTUBE SURFACE MODIFICATION ON STRUCTURAL PROPERTIES OF POLYIMIDE BASED
NANOCOMPOSITES
A.D. Glova1, E.B. Serebryakov1, S.V. Larin2, S.V. Lyulin2 1 - St. Petersburg State University, Physical Faculty, St. Petersburg, Russia
2 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russia [email protected]
At the present time carbon nanotubes (CNT) belong to a class of nanoparticles that attracts high attention of researches due to their extraordinary mechanical, thermophysical, and electrical properties. Development of composite materials filled with CNTs is one of the promising ways to produce high-performance construction materials. Addition of CNT in the polymer matrix can result in sufficient structural changes of the polymer. CNT can act as a nucleant and induce polymer crystallization in composites. As far as composite components interact only in the interface region the thickness of this region and polymer matrix structure there are crucial parameters influencing composite properties. At the same time CNTs in polymer matrix often aggregate that leads to the decrease of the interface surface region and can negatively impact composite properties. The modification of the nanotube surface is one of the techniques to avoid aggregation of CNTs in polymer matrix. In the present study the influence of the CNT surface modification on the structural properties of polymer matrix in polyimide-based composites is investigated by means of extensive molecular dynamics (MD) computer simulations. Two types of polyimides R-BAPB and R-BAPS which were synthesized and studied in the IMC RAS were considered as polymer matrix. The functionalized carbon nanotubes (f-CNT) with carboxylic groups attached to the surface were used as a filler. f-CNTs with the surface modification degree ω = 5 % and 10 % were considered. Recently we show that the addition of CNT to R-BAPB polyimide induces formation of layered structure in the polymer matrix that could be the initial stage of polymer crystallization [1]. Analysis of the polymer matrix structure in composites filled with f-CNTs of different surface modification degree was performed for the systems calculated with and without electrostatic interactions. The influence of electrostatic interactions on the interaction strength of PIs with CNT and on the structure of composites was investigated. In case of systems without electrostatic interactions it was found that the formation of layered structure in the R-BAPB based composites could be observed only in case of ω = 5 %. For composites filled with f-CNTs with ω = 10 % no structural ordering of polymer matrix was observed for both polyimides. This behavior can be explained by effective screening of polymer interactions with f-CNT surface with increase of surface modification degree. The simulations have been performed using the computational facilities of the Institute of Macromolecular Compounds, Russian Academy of Sciences, and the Chebyshev and Lomonosov supercomputers at Moscow State University. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002 and Russian Foundation for Basic Research (grant #13-03-00547) 1. S.V. Larin, S.G. Falkovich, V.M. Nazarychev, A.A. Gurtovenko, A.V. Lyulin, S.V. Lyulin. RSC Adv. 2014. V. 4. P. 830-844.
P-154 SOPRTION PROPERTIES OF THE COMPOSITES CONTAINING CHITIN AND CHITOSAN LAYERS ONTO POLYETHYLENE POROUS
FILMS
E.Yu. Rosova1, N.N. Saprykina1, G.A. Tiscenko2, G.K. Elyashevich1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia
2 - Institute of Macromolecular Chemistry, Prague, Czech Republic [email protected]
The prospects of natural polysaccharides application is related to their advantages – biocompatibility, biodegradation, nontoxicity and capability to selective sorption of organic substances and heavy metals. However, the problem is a low solubility of these polymers, and insufficient strength and elasticity of their films. Moreover, high swelling of the chitosan films in vapor phase of solvents considerably restricts their utilization. Thus, preparation of polysaccharides film materials with high sorption selectivity and good mechanical properties is an important task. New composite systems prepared by deposition of the natural polysaccharides layers – chitin, chitosan and their mixtures – on the porous polyethylene film have been elaborated. Surface morphology, sorption and mechanical properties of the composite films were investigated. Commercial chitosan (Aldrich) with Mw = 408 kDa, concentrated aqueous -chitin nanofibers (chiNF) suspension (slender rods with width and length 5-70 and 150-800 nm, respectively) (MaviSud S.r.l., Italy) as active components and PE porous film as support were used. PE porous films obtained in the process based on melt extrusion are characterized by a strongly developed relief-like surface. They contain open-to-surface and through-flow pores, both. Casting technique to form the chitin-chitosan layer was realized using 2% chitosan solution in 2% acetic acid, concentrated aqueous chiNF suspension and their mixture (in the ratio 1:1). The solutions were casted on the PE porous support, and then composite films were dried at 300C during 24 h. Thickness of the films depended on the sample composition: 35 mkm for PE-chitosan films, and 50 and 95 мкм for PE-chiNF and PE-mixture, respectively. The high adhesion of the layers to PE support was observed. It was shown that the adhesion is due to the porous structure of the PE films and specific character of their surface. Some exfoliation of the layer from PE support was observed at deformation for the PE-chiNF sample, only. It was shown by SEM that polysaccharides layers on PE films were smooth and uniform, and completely masked the relief surface of the porous support. However, a small cracks can be seen on the SEM pictures of PE-chiNF samples at high magnification. Sorption behavior of the composite systems in solvents vapours have been investigated. It is shown that the samples entirely preserve the sorption-selective properties of the neat polymers – chitin and chitosan. At the same time they demonstrated a limited swelling in solvents vapours that may be explained by the formation of polysaccharides phase inside the pores of PE film which fixes a composite structure. It was not observed any failure of the composites up to the high swelling degrees. It was proved that prepared composites have a high sorption-selective properties of neat polysaccharides and also a good mechanical properties of the porous polyethylene support. The work was supported by Russian Foundation of Basic Research (Grant № 13-03-00219-a and 13-03-12071-ofi-m) and Cooperation Project between Academy of Sciences of the Czech Republic and Russian Academy of Sciences.
P-155 COMPOSITES BASED ON CARBOXYMETHYL CELLULOSE WITH ARABINOGALAKTAN
I.L. Shevtchuk1, A.M. Bochek1, N.M. Zabivalova2, V.K. Lavrent’ev1, I.V. Gofman1,
M.F. Lebedeva1, E.N. Popova1, I.V. Abalov1, V.E. Yudin1 1 - Institute of Macromolecular Compounds of Russian Academy of Sciences, St.Petrsburg, Russia
2 - Inmed , LLC, 2A Kashirskaya st., St.Petersburg, Russia [email protected]
Rheological properties of aqueous solutions of mixtures of carboxymethyl cellulose (CMC) with arabinogalactan (AG) isolated from Siberian larch were investigated for expansion of the range of polysaccharides using. Physical-mechanical properties of obtained composite films and their structure and compatibility of the polymers in solid state were also studied. In dilute (0.05%) solutions of mixtures negative deviation in viscosity of systems from additive values was observed. For concentrated solutions of polymer mixtures (2% mass) the positive deviation in viscosity from additive values was observed indicating on the forming of the more stable structure of concentrated solutions in comparison with structure of the initial solutions of CMC with AG. Composite films had satisfactory stress-strain characteristics. Composite films with content of AG till 20% possessed the following stress-strain characteristics: modulus of elasticity 3.5 GPa, tensile strength 88 MPa and elongation at break 20%. X-ray scattering experiments on composite films showed that superposition in reflexes of one polymer on another occurred depending on the film composition. The formation of new structures was not observed. Using the methods of dynamic mechanical analysis, thermo-mechanical analysis and differential scanning calorimetry and thermo-gravimetric analysis the values of the relaxation transitions temperature in the systems under study were determined, the regions of compositions where CMC was compatible with AG were found, and the film composites thermal stability was investigated. It was shown that partial compatibility was observed for composites. In composite films with a content AG up to 70% the single temperature transition was observed, that testified about compatibility of polysaccharides. This work was supported by Russian Foundation for Basic Research (Project № 13-03-00584).
P-156 PROPERTIES OF AQUEOUS SOLUTIONS AND FILMS FROM MIXTURES OF METHYL CELLULOSE WITH ARABINOGALACTAN
A.M. Bochek1, N.M. Zabivalova2, V.K. Lavrent’ev1, I.V. Gofman1, M.F. Lebedeva1, E.N. Popova1,
I.V. Abalov1, V.E. Yudin1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia
2 - Inmed LLC, 2A Kirishskaya, St.-Petersburg, Russia [email protected]
Rheological properties of aqueous solutions of mixtures of methylcellulose (MC) with arabinogalactan (AG) isolated from Siberian larch, structure and the physical - mechanical properties of composite films and compatibility of polymers in the solid state have been studied in order to create a composite film materials with new functional properties and controlled stress-strain characteristics for biomedical purposes. In dilute (0.2%) solutions of mixtures at a content of AG up to 15 wt%. positive deviation in viscosity of systems from additive values was found. At higher content of AG in mixtures negative deviation from the additive values of viscosity was observed, that indicated on a possible interaction of MC macromolecules with AG in solutions. For concentrated solutions of polymer mixtures the positive deviation of viscosity from additive values only occurred indicating that the formation of the more stable structure of concentrated solutions in comparison with the structure of the initial solutions of MC and AG. It was shown that with increasing concentration of AG in mixtures the growth in temperature of the onset of gelation in solutions took place due to the dilution effect of gell-forming polymer MC. Composite films having satisfactory stress-strain characteristics were obtained. Introduction of AG up to 30 wt. % into the matrix MC did not lead to the significant worsening in the properties of composites. At higher content of AG the deterioration of stress-strain characteristics of the films was found. X-ray scattering experiments on composite films showed that superposition in reflexes of one polymer on another occurred depending on the film composition. At introduction of AG in matrix MC the crystallization process of polysaccharide was changed and imperfection of the crystal structure of MC increased. In the range of compositions in which MC was incompatible or partially compatible with AG the mixed amorphous structural formations were arisen. The values of the relaxation transition temperature in systems under study were determined by dynamic mechanical analysis, thermo-mechanical analysis, DSC and TGA, and the fields of compositions in which MC was compatible with AG were determined. It was shown that the glass transition temperature was 212°C. In composite films with a content AG up to 50% the single temperature transition was observed, that testified about compatibility of MC with AG in indicated composition range. This work was supported by grant of Russian Foundation for Basic Research ( №13-03-00584)
P-157 SOLUTIONS OF CELLULOSE AND CHITIN IN AQUEOUS ALKALINE MEDIA WITH ADDITION OF UREA AND THIOUREA AND
STRUCTURE OF REGENERATED POLYSACCHARIDES
A.M. Bochek1, I.V. Serov2, N.P. Novoselov2, N.M. Zabivalova1, V.K. Lavrent’ev1, B.Z. Volchek1, E.N. Vlasova1, N.N. Saprykina1
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia 2 - Saint-Petersburg State University of Technology and Design, Saint-Petersburg, Russia
Peculiarities of dissolution of cellulose (Cell) and chitin (Chit) in aqueous alkaline solutions with addition of urea and thiourea, rheological properties of solutions and structure of regenerated polysaccharides have been studied for the purpose of development of safe processing practice of natural polymers in fibers and films. It was shown that Cell was solved in two-component (NaOH/urea) and ternary (NaOH/urea/ thiourea) aqueous systems, while Chit was solved well only in ternary mixtures. In dependence on the dissolution conditions and the preliminary treatment of Cell in systems under study from 25 till 100% natural polymer was dissolved. Cell with degree of polymerization (DP) till 500 was found to turn into solution and Chit with DP = 300. Concentrated solutions of Cell and Chit were obtained and their rheological properties were investigated. At heating of Cell and Chit solutions and also during their storage at room temperature the gelation was observed which depended on solvent composition (two-component or ternary) and conditions of solutions treatment. Films of cellulose hydrate and Chit were obtained by wet forming method and their structure was studied by Fourier IR-spectroscopy and X-ray diffraction. Regenerated cellulose was found to fit polymorphous form Cell II with the low degree of ordering. Regenerated Chit also had the low degree of ordering as compared with that of initial chitin. Morphological peculiarities of cellulose hydrate films were studied by electron microscopy technique. It was shown that morphology of films was heterogeneous and the compacted structural formations were observed in it.
P-158 COMPOSITES BASED ON CARBOXYMETHYLCELLULOSE WITH POLY-N-METHYL-N- VINYLACETAMIDE AND
CARBOXYMETHYLCELLULOSE WITH COPOLYMER METHYLVINYLACETAMIDE AND HYDROCHLORIDE
METHYLVINYLAMINE
I.L. Shevchuk, L.M. Kalyuzhnaya, A.M. Bochek, I.I. Gavrilova, V.K. Lavrent’ev, I.V. Gofman, M.F. Lebedeva, E.N. Popova, I.V. Abalov, V.E. Yudin, E.F. Panarin
Institute of Macromolecular Compounds of Russian Academy of Sciences, St.-Petersburg [email protected]
Rheological properties of aqueous solutions containing mixtures of carboxymethylcellulose (CMC) of different ionization degrees with poly-N-methyl-N-vinylacetamide (PMVAA) and CMC with copolymer methylvinylacetamide and hydrochloride methylvinylamine (MVAA-HMVA), structure and stress-strain characteristics of composite films have been studied for obtaining composite film materials with new functional properties for biomedical purposes. Positive viscosity deviations from additive values were found in concentrated aqueous solutions of mixtures CMC-PMVAA and CMC- MVAA- HMVA. Films have been obtained from solutions by dry forming method. Their structure, physical and mechanical properties as well as thermodynamic compatibility of polymers in solid state have been investigated. X-ray scattering experiments on composite films showed that the formation of new mixed structures did not take place. Dynamic mechanical analysis (DMA), thermo-mechanical analysis (TMA) and vapor sorption method have been used for the study of polymers compatibility in solid state. The partial polymers compatibility was determined for all systems under study. The transformation of NaCMC into HCMC leads to reduction of composition range in which polymers are compatible due to the increase in interaction between carboxyl groups of CMC. Composite films containing up to 20 mass.% PMVAA or copolymer MVAA- HMVA were shown to possess satisfactory stress-strain characteristics.
P-159 PHOTOLUMINESCING PROPERTIES OF BLENDS OF COPOLYFLUORENES, CONTAINING GREEN AND RED
I.A. Berezin, G.I. Nosova, R.Yu. Smyslov, D.M. Ilgach, T.N. Nekrasova, A.V. Yakimansky
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, 199004 St. Petersburg, Russia [email protected]
The interest to conjugated copolyfluorenes (CPF) is caused their applications in optoelectronic devices and the possibility to tune photoluminescence (PL), electroluminescence (EL), and charge-transporting characteristics of these devices, varying the chemical structure of polymers. However, it is difficult to control such properties of copolymers as PL and EL emission color. This circumstance is due to the nonlinear dependence of the film morphology and optoelectronic properties on the content of luminophore and charge-transporting units in CPFs. In the present work, a series of CPFs was synthesized by Suzuki polycondensation method and used to prepare homogeneous blends of a widely varied composition. The polymers contained electron-donor carbazole and electron-acceptor diphenyloxadiazole fragments (charge-transporting groups) and either green or red luminophore. As red luminophores, Nile red derivatives or 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (T-BT-T) fragments were used. Green-emitting polymers contained units of 2,1,3-benzothiadiazole or naphthalimide derivatives. The effect of terminal groups on the emission color tones of polymer films is also analyzed. The process of the photoexcitation energy transfer from fluorene to luminophore moieties in blends of CPFs is studied as well. It is established that in order to get white emission, i.e. to preserve emission in the whole visible range, the total content of green and red luminophores in a blend should not exceed 0,5 mol %. This requirement is satisfied in blends based on CPFs with Nile red (0.15 mol %) and naphthalimide (up to 0.5 mol %) units, displaying white PL in films. The replacement of >0.2 mol % benzothiadiazole for naphthalimide luminophore led to a hypsochromic 40 nm shift in the maximum of Nile red emission, and, as a result, one broadened emission band was observed with an insufficient intensity in the long-wave red spectral range. To prepare white-emitting films, it was necessary to use lower concentrations of benzothiadiazole (about 0.1 mol %). A monochromic green or red emission is observed for blends prepared of CPFs, containing 1-10 mol % of one of the corresponding luminophores. Combining green benzothiadiazole and red T-BT-T luminophores in blends of CPFs gives rise to an intense transfer of the excitation energy from fluorene and green luminophore groups to red luminophore fragments. In order to enhance red EL, blends of CPFs were studied with 8 mol % benzothiadiazole and 2 mol % of T-BT-T. Based on the obtained results, CPFs, containing both green and red luminophores were synthesized, which possess a predefined photoluminescence with the color properties close to those obtained for binary blends of two CPFs, containing only one of the respective luminophores. Further experiments on the preparation of OLEDs form the studied CPF materials and investigations of their EL properties are planned. The work is supported by the Scientific Program of the Presidium of the Russian Academy of Sciences “Multifunctional materials for molecular electronics” (coordinator – academician S.M. Aldoshin) and by the grant U.M.N.I.K for I.V. Berezin
P-160 NANOCOMPOSITES OF POLYPYRROLE NANOTUBES WITH NOBLE METALS
I. Yu. Sapurina1, J. Stejskal2, J. Kopecka3
1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St-Petersburg 199004, Russia; Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic
2 - Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic
3 - Faculty of Chemical Engineering, Institute of Chemical Technology Prague, 166 28 Prague 6, Czech Republic [email protected]
Nanoparticles of noble metals, such as Pt, Pd, Rh, Au, Ag, are promising in heterogeneous catalysis and electrocatalysis, sensing, biomedical applications and applications in electronic and energy-storage devices. Integration of noble metals with conducting polymers allows for not only combined properties of the original components, but it may also lead to a synergistic effect of amplification. The control of the morphology of the polymer and the metal nanoparticles is extremely important. This allows changing the properties of metal-polymer composite over a wide range. Nanoparticles of noble metals were directly synthesized through polypyrrole mediated technique utilizing the donor–acceptor and redox chemistry of polypyrrole and its capability to stabilize the metals nanoparticles (Fig. 1). Composites contain 10–20 wt.% of metal. Metal in the form of nanoparticles having a size of units or tens of nanometres are localized on the surface of polypyrrole nanotubes.
Fig. 1. The composite of polypyrrole nanotubes with Pt nanoparticles and its EDAX characterization.
Element Weight % Atomic % C K 37.5 76.4 O K 3.6 5.5 S K 0.6 0.4 ClK 1.7 1.2 CaK 0.3 0.2 CuK 35.7 13.7 PtL 20.6 2.6 Total 100.0 100.0
P-161 MONODISPERSE POLYSTYRENE PARTICLES WITH INCORPORATED COLLOIDAL QUANTUM DOTS
D.I. Shevaldysheva1, T.G. Evseeva1, V.V. Zakharov2, A.V. Veniaminov2, N.N. Shevchenko1
1 - Institute of Macromolecular Compounds RAS 2 - Saint- Petersburg national Research University of Information Technologies, Mechanics and Optics
Fluorescent polystyrene particles have been synthesized via emulsion and seeded emulsion polymerization using trioctylphosphine oxide (TOPO)-coated CdSe/ZnS core-shell quantum dots (QDs). The influence of the emulsion preparation method, concentrations of QDs and cross-linking agent, type of the surfactant and seeded particles on photoluminescent properties of prepared particles was analyzed. The latexes exhibited particle sizes from 70 to 2000 nm, narrow particle size distribution, and self-assembling to three-dimensional ordered structures was obtained in all cases. The obtained fluorescent particles and structures based on them open up new opportunities for a variety of applications in optoelectronics. Polymerization methods leading to polymer colloids are well known and well developed for numerous polymer systems. In many instances, monodisperse polymer micro- or nanospheres can be obtained, and the diameter of the polymer colloids can be tuned from the micrometer to the sub-100 nanometer scale. Many efforts have therefore been focused on incorporating QDs into well-defined polymeric particles via monomer polymerization in a dispersed media. Monodisperse hybrid particles of a certain diameter can be used as the main structure-forming elements due to their availability and ability to self-assemble into three-dimensional ordered arrays with periodically modulated refractive index. Narrow particle size distribution of these hybrid “building blocks” makes it possible to control the period of distribution of quantum dots, which is promising for the realization of a “superluminescence” effect. Monodisperse hybrid nanoparticles were prepared by emulsion copolymerization of styrene and N-vinilformamide in the presence of hydrophobic TOPO-coated quantum dots CdSe/ZnS. It was shown that a preliminary dispergation of quantum dots in the comonomer mixture with ultrasonication provides a stable, monodisperse hybrid particles, which can self-assemble into three-dimensional ordered structures, and display the luminescence intensity five times higher than that attained without a predispergation. Hybrid core-shell microspheres were obtained by the method of seeded emulsion polymerization of styrene in the presence of the hydrophobic quantum dots. In the first step, monodisperse seed cores were synthesized by means of dispersion or surfactant-free emulsion polymerization of styrene. The effect of the shell synthesis conditions in the presence of hydrophobic quantum dots (concentrations of QDs and styrene, styrene/cross-linking agent ratio, the nature and concentration of the initiator, the method of predispergation of quantum dots in the oil phase) on the luminescence intensity of hybrid monodisperse particles and films based on them was investigated.. Surfactant-free emulsion copolymerization of styrene and N- vinylformamide or methacrylic acid in the presence of hydrophobic QD were studied for synthesis of hybrid particles having a diameter in the submicron range. Presence semiconductor nanocrystals in the reaction system leads to the formation of hybrid bimodal particles not able to self-assemble into three-dimensionally ordered structure. In order to obtain monodisperse hybrid particles with diameter in the submicron range the quantum dots infiltration in the surface layer or in the bulk of the monodisperse polymer particles of submicron poly(styrene-co-methacrilic acid) were investigated It is shown that after infiltration and removal of the organic solvent hybrid particles can self-assemble into a three-dimensionally ordered structures. This work was supported by the Russian Foundation for Basic Research (project no. 13-03-00741).
P-162 INFLUENCE OF FERROCENE CONTAINING PLASTICIZER ON THE PROCESS OF STRUCTURING A CARBOXYLATE RUBBER – EPOXY
RESIN SYSTEM
E.Yu. Nesterova, T.V. Sharovatova Dnepropetrovsk National University, Ukraine
Nowadays we observe wide application of terminal oligomeric rubbers with side carboxyl groups. Besides sufficiently high chemical resistance, rubbers are characterized by excellent deformation properties. However, they have low hardness, low thermal resistance and adhesion. The introduction of the epoxy component into the rubber leads to the improvement of dynamic endurance, physical, mechanical and performance properties of the rubbers. It is known that introduction of ferrocene in the polymer system leads to increase their thermal and radiation stability and to improve of electrostatic properties. This work is devoted to the development of new plasticizers containing ferrocenyl fragment based on the modified castor oil and ferrocene derivatives, as well as to the research of their effect on the kinetics of curing of the system carboxylate rubber - epoxy resin. We have developed a technique to obtain a plasticizer based on the product of glycerolizes of castor oil and ferrocencarbonic acid (FMRO). Using the method of DSC we showed high plasticizing capacity of FMRO. It is found out that during its introduction into the carboxylate rubber glass transition temperature of the rubber undergoes a significant shift to the range of lower temperatures. The kinetic of curing reaction in the system “carboxylate rubber - epoxy resin” was studied. The investigation showed that the reaction is bimolecular; this process conforms to the kinetic equation of a second-order reaction and has mainly the first order in each reactant. It was found out that the constant of reaction rate has its maximum value at a molar ratio of rubber:epoxy resin = 1:2. It is shown that the FMRO as a plasticizer in the system “carboxylate rubber - epoxy resin” has the greatest influence on the reaction capacity both carboxylic and epoxy groups. As a standard of comparison are used systems with dioctyl ester of decandioic acid (DEDA) as a plasticizer. Studied in more detail the effect of the ferrocene plasticizer on the kinetics of the curing reaction in the system of carboxylate rubber : epoxy resin at different temperatures (70, 80, 90, 100, 110) (see Fig.1,2).
Fig.1 Flow curves of the carboxyl groupsby heating compositions "carboxylaterubber - epoxy resin": without plasticizer,with 4%, DEDA, with 7% DEDA, with 7%FMRO. (heating 240 min.)
Fig.2. Flow curves of the epoxy - groupsby heating compositions "carboxylaterubber - epoxy resin": without plasticizer,with 4% DEDA, with 7% DEDA, with 7%FMRO. (heating 240 min.)
P-163 REINFORCED COMPOSITES BASED ON UHMWPE AND CONDUCTIVE NANOSCALE CARBON FILLERS
O.V. Lebedev1, A.S. Kechek’yan2, V.G. Shevchenko2, T.S. Kurkin2, A.N. Ozerin2
1 - Moscow Institute of Physics and Technology (State University) 2 - Enikolopov Institute of Synthetic Polymer Materials of RAS
This work describes the structure and properties of electrically conductive nanocomposites with enhanced strength received in conditions of the homogeneous shear (HS), which are available through the deformation of specimens of the nanocomposites placed between the facings made of ductile metal and by forcing them through dies with different diameters of holes [1]. The tensile strength of the electrically conductive composites is significantly higher than for nonoriented composites of the same composition. The examined samples of polymer composites are based on reactor powder of the ultrahigh molecular weight polyethylene (UHMWPE) [2]. The fine powders of graphite, carbon nanotubes (CNT) and commercial carbon black were used as the fillers. The components were mixed in hexane using ultrasonication. The dried mixture of UHMWPE and filler powders were compression molded at the room temperature, and then deformed in conditions of the HS mentioned above. The structure and properties of composites were studied by WAXS and SAXS methods, as well as by electrical conductivity and mechanical characteristics measurements and SEM. The relationship of the conductivity of the molded composite vs electrically conductive filler weight content had the threshold nature, with the values of percolation threshold of ~ 4 wt-% for graphite, 1.5 wt-% for carbon black and 0.25 wt-% for CNT. The increase in extension ratio in conditions of the HS leads to the growth in the percolation threshold value, while increasing the values of the tensile strength at the same time. The relationships of conductivity vs the extension ratio in conditions of the HS, which were observed for samples with the fixed content of the filler, have a threshold nature also. For example, for the sample with 4.3 wt-%. of graphite, the conductivity disappeared when extension ratio in conditions of the HS reached a value ~ 7. In the study of small (10-15% relative strain) elastic deformation of composites in the direction of the axis of orientation the reversibility of the resistance under the condition of reversibility of the deformation was noted, with a coefficient of about 0.3-0.4 kOhm/(% of elastic deformation) for optimized with respect to a maximum in elastic-strength and conductive characteristics composite. A comparison of the structure and properties of hardened electrically conductive composites of various compositions received in conditions of the HS at room temperature and under the continuous molding at an elevated temperature was carried out. The proposed approach allows, for example, when using a fine graphite as a filler, to obtain an electrically conductive polymer composite material, optimized with respect to a maximum in elasto-mechanical and electroconductive characteristics, which has the initial elastic modulus of 1.1-1.3 GPa, the tensile strength of 65-100 MPa, the elongation at break of 10-30%, resistivity of 10-103 Ohm*cm, and a reversible electrical resistivity changing when a small elastic deformation in the direction of the axis of orientation is applied. Acknowledgments: This work was supported by the Russian Foundation for Basic Researches (grant # 14-03-01120). [1] Kechek’yan, A.S., Mikhailik, E.S., Monakhova, K.Z., Kurkin, T.S., Gritsenko, O.T., Beshenko, M.A., Ozerin, A.N. Doklady Chemisty, 2013, 449, Part 1, 94 [2] Ozerin, A.N., Ivanchev, S.S., Chvalun, S.N., Aulov, V.A., Ivancheva, N.I., Bakeev, N.F. Polymer Sci., Ser. A, 2012, 54, No.12, 950
P-164 MECHANICAL BEHAVIOR OF SUPER-TOUGH COMPOSITE HYDROGELS DURING SWELLING-DESWELLING EXPERIMENTS
A. Buyanov, I. Gofman
Institute of Macromolecular compounds RAS, St.-Petersburg, Russia [email protected]
Composite bi-component hydrogels with the cellulose-polyacrylamide interpenetrating networks (IPN) structure are characterized by extremely high level of the mechanical properties, substantially exceeding those of other types of hydrogels known up to date. These unusual properties originate in the high stiffness of cellulose macrochains which act as a “scaffold” hardening the IPN and at the same time restricting the extent of swelling of polyacrylamide, the synthetic component of this IPN. In this situation the polymer components of the IPN under consideration are in the constrained state that insures the substantial increase of the mechanical stiffness of these hydrogels [1]. We have tried to verify this assumption experimentally. For this purpose the hydrogel samples swollen in water up to the equilibrium state were subjected to the mechanical tests. Then the swollen samples were exposed to the deswelling process by adding ethanol to water in which these samples were swollen with the stepwise increase of the ethanol concentration in the mixture. These tests have shown that after the deswelling process, which leads to the increase of the volume fraction of polymer in the hydrogel , the stiffness of the gel samples (the compression modules and the compression stress values) does not increase. These mechanical characteristics remain constant or decrease. The same effect was obtained by using the water-plyethylene glycol (PEG) mixtures for deswelling, or by the variation of the pH value of the swelling medium in case of poly-electrolite hydrogels (cellulose-hydrolyzed polyacrylamide). For the stiffest types of the hydrogels the above mentioned characteristics become several times fewer after deswelling (Fig. 1). This behavior is anomalous from the viewpoint of the theory, developed for the mono-component networks. For example, the equation of high elasticity E3RT1/3 predicts the increase of the modulus value caused by the deswelling process, the extent of this increase being proportional to 1/3. But the above described experimental effect can be interpreted correctly if taking into account the constrained state of the components of IPN, existing in our hydrogels: during the deswelling the gradual transition of the coils of polyacrylamide flexible chains to the -state takes place that provokes the decrease of extent of constrains of the IPN components resulting in the depression of the hydrogel stiffness.
10 20 30 40 50
4
8
12
16
20
Str
ess,
MP
a
Compression, %
1
2
Fig 1. Stress-strain curves of a stiff cellulose-polyacrylamide hydrogel sample swollen in water up to the equilibrium state (1) and of the same hydrolyzed gel swollen in the water-PEG mixture (2). References 1. A. L. Buyanov, I. V. Gofman, A. K. Khripunov, A. A. Tkachenko, and E. E. Ushakova. Polymer Science, Ser. A. 2013. V. 55. No. 5. p. 302–312.
P-165 BIQUINOLYL-DICARBOXYLIC ACIDS – NEW BIFUNCTIONAL MONOMERS FOR THE SYNTHESIS OF MACROMOLECULAR LIGANDS
N.S. Guliy1, M.Ya. Goikhman2, I.V. Podeshvo1, N.L. Loretsyan1, I.V. Abalov1, I.V. Gofman1,
T.D. Anan’eva1, A.V. Yakimansky1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr.31, Saint-Petersburg, 199004,
Russia 2 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004
Russia; St. Petersburg State University, Institute of Chemistry, Universitetskii pr. 26, Petrodvorets, St. Petersburg, 198504, Russia
Macromolecular ligands with biquinolyl-containing units in the main chain are initial compounds for the creation of metal-polymer complexes with salts of such transition metals as Cu(I), Ru(II), etc. A specific chemical structure of the indicated metal-polymer complexes predetermines their optical and redox (electrocatalytic) properties as well as differences in architecture of complexes formed by metals with various coordination numbers, and causes features of their thermomechanical and transport (membrane) properties. Earlier synthesized polymers on the basis of 2,2’-biquinolyl-4,4’-dicarboxylic acid showed themselves as prospective coatings for electrodes used in electrocatalytic properties and as materials for pervaporation and gas-separating membranes. It was also found that it was possible to control membrane and electrocatalytic properties of these polymer materials, varying the rigidity of polymer chains. In particular, such variations in the polymer chain rigidity may be realized via the introduction of biquinolyl fragments with functional substituents at the positions other than 4,4’. To this aim, we developed a method of the synthesis of new bifunctional biquinolyl-containing monomers: 2,2’-biquinolyl-6,6’-dicarboxylic acid, 2,2’-biquinolyl-7,7’-dicarboxylic acid, and 2,2’-biquinolyl-8,8’-dicarboxylic acid.
NH
O
O
CH3
CH3
OH
O
NN
OHOOOH
O
NH2
OK
O
NN
NN
H2O2
NN
SeO2
H
OO
HOH
OO
OH
methylisatin
KOH
2,2/-biquinolyl - dimethyl-4,4/ -dicarboxylic acid
Cu, 300 0C
- 2 CO2
dimethyl-2,2/ -biquinolyl
(83%) (75%)
acetoine
diformyl-2,2/-biquinolyl 2,2/-biquinolyldicarboxylic acid
The structures of all synthesized compounds were confirmed by the methods of 1H and 13C NMR-spectroscopy and elemental analysis. Dichloroanhydrides of the indicated dicarboxylic acids were used as monomers for polycondensation.
P-166 SYNTHESIS AND ELECTROCHEMICHAL PROPERTIES OF POLY(ORTHANILIC ACID-CO-ANILINE) NANOPARTICLES
M.A. Smirnov, I.Yu. Dmitriev, P.V. Vlasov, G.K. Elyashevich
Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia [email protected]
Aniline (ANI) was copolymerized with orthanilic acid (ORT) in aqueous HCl solution using (NH4)2S2O8 as an oxidant. This reaction permits to form a practically perspective self-doping sulfonated polyaniline. Set of the samples was prepared by variation of comonomer ratio in polymerization mixture: mole fractions of ORT were 0, 17, 33 and 50% in relative to the sum of monomers. Synthesis was carried out in the temperature controlled vessel at 0°C with registration of open-circuit potential (OCP) of Pt-electrode in the reaction medium versus silver chloride reference electrode (SCE). This technique makes it possible to control the kinetic parameters of ANI (or its derivatives) oxidative polymerization on the following stages: induction period, nucleation of polymer particles, and their growth in autocatalytic reaction between (NH4)2S2O8 and monomers. It is shown (fig.1) that addition of ORT to the polymerization mixture increases the duration of all stages. Detailed analysis of OCP-curves has allowed to reveal that propagation stage, induction period and nucleation stage slow down from 10 to 70, from 1 to 11 and from 4 to 10 minutes, respectively. Thus, the lowest change of duration takes place on the nucleation stage. Because ORT is less active in an oxidative polymerization than ANI one can suppose that ORT is integrated in the polymer chains mostly on the stage of particle growth. At the same time the nucleates essentially consists of ANI residues.
0 25 50 75 100
600
700
800
900
4321
Polymerization time / min
E v
s. S
CE
/ m
V
0 400 800
-20
0
20
x(ORT) / mol %
Cu
rren
t / m
A
0% 17% 33% 50%
Potential / mV vs. SCE
Fig.1. Open circuit potential profiles for copolymerization of ANI with content of ORT: 1 –0%, 2 – 17%, 3 – 33% and 4 – 50%.
Fig2. Voltammograms for copolymers with various content of ORT (in 1M HCl solution).
Electrochemical activity of the copolymers was investigated by cyclic voltammetry (fig.2). The curve for ANI gomopolymer demonstrates three peaks: 0.18, and 0.8 V 0.51 V . The first and the last peaks can be attributed to two-step transition between different forms of polymer: from leucoemeraldine (the lowest oxidation one) through emeraldine to the pernigraniline (the highest oxidation one). The middle peak is attributed to the presense of phenazine rings. According to literature these groups are formed during induction period of polymerization and acts as constructing material for nucleats of polymer particles. Increasing of ORT content in the polymerization mixture leads to disappearance of 0.81 V peak. This observation can be explained by the fact that the electron-seeking effect of sulfo-groups obstructs the oxidation of polymer into the pernigraniline. At the same time the peak at 0.51 V remaines at the same position for all samples that confirms the conclusion made above that nucleats are constructed from the products of ANI gomopolymerization. The work was supported by Russian Foundation of Basic Research (Grant № 13-03-00219-a and 14-03-31411 mol-a).
P-167 INTERFACIAL INTERACTIONS AND DYNAMICS IN THERMOSETTING POLYURETHANE NANOCOMPOSITES WITH ULTRA-LOW MULTI-WALLED CARBON NANOTUBE CONTENTS
V.A. Bershtein1, L.V. Karabanova2, R.L.D. Whitby3, A.V. Korobeinyk3, P.N. Yakushev1,
O.M. Bondaruk2, A.W. Lloyd3, S.V. Mikhalovsky3 1 - Ioffe Physical-Technical Institute, RAS, 194021 St.-Petersburg, Russia
2 - Institute of Macromolecular Chemistry, NAS, 02160 Kyiv, Ukraine 3 - Nanoscience and Nanotechmology Group, Faculty of Science and Engineering, University of Brighton BN2 4GJ,
Brighton, UK [email protected]
Polyurethanes (PU) are extensively used in biomedical and technical applications. In this work, the thermosetting PU-MWCNT nanocomposites with 0.01, 0.1 or 0.25 wt.% nanofiller and varied, strictly controlled chemical situation at interfaces were prepared and characterized1,2 using chemical analysis, SEM, TEM, DMA, stress-strain testing and laser-interferometric creep rate spectroscopy (CRS)3 techniques. Via acid oxidation and reduction procedures, carboxyl, phenol and other functional groups to be used as cross-linking sites to the matrix were generated on the MWCNT surface. These groups were attached to the MWCNT surface either directly through covalent bonding or by van der Waals forces only, through an intermediate polycyclic aromatic hydrocarbon (hemin) layer as an analogue of fulvic acids appearing on nanotubes as a result of their acid oxidation. A good nanotube dispersion in the matrix was shown for the nanocomposites with MWCNT contents of 0.01 and 0.1%, whereas both individually separated nanotubes and their small, loosely packed agglomerates were present in the matrix at 0.25% nanotubes. The strong dependence of nanocomposite glass transition dynamics and mechanical performance on variations in the nanotube surface chemistry was demonstrated: the large impact of MWCNTs was observed only at direct covalent bonding between PU matrix and nanotube lattice, which was purified from fulvic acids. The pronounced dynamic heterogeneity within the PU glass transition covering 2000 range was registered in the nanocomposites studied from DMA analysis of motion activation energy Q(T) plots and creep rate spectra due to the “constrained dynamics” effects and different motional cooperativities. The displacements of main PU relaxation maximum from around 0 to 80-1400C in the complicated DMA and creep rate spectra were shown at direct covalent attaching of matrix to carbon nanotube lattice that provided an efficient load transfer between the nanofiller and the matrix. Due to the cardinal changes in fundamental interaction at the interfaces and molecular dynamics in the matrix, two- or threefold enhancement in mechanical properties (static and dynamic moduli, stress at break), compared with those of neat PU matrix, was attained by using MWCNTs with covalently attached functional groups. The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/ under REA grant agreement PIRSES-GA-2013-612484. The work was also supported by the Ukrainian project № 6.22.7.21 of the STSTP “Nanotechnology and Nanomaterials”.
References 1. L. V. Karabanova, R. L. D. Whitby, V. A. Bershtein, A. V. Korobeinyk, P. N. Yakushev, O. M. Bondaruk, A. W. Lloyd, S. V. Mikhalovsky. Colloid Polym. Sci. 291, 573-583 (2013). 2. L. V. Karabanova, R. L. D. Whitby, A. V. Korobeinyk, O. M. Bondaruk, A. W. Lloyd, S. V. Mikhalovsky. Comp. Sci. Technol. 72, 865-870 (2012). 3. V. A. Bershtein, P. N. Yakushev. Adv. Polym. Sci. 230, 73-219 (2010).
P-168 ORGANOSILOXANE ADHESIVE SEALANTS WITH IMPROVED PHYSICOMECHANICAL PROPERTIES
T.M. Chigorina, A.A. Arutyunyants, V.T. Abaev
North Ossetian State University, Vladikavkaz, Russia [email protected]
The development of contemporary science is impossible without creating polymer materials, which yield high and stable characteristics of goods during exploitation. Silicon-organic compounds (silicons) and materials based on them are necessary for developing and currently revealing the most important branches of technics and national economy; this is conditioned by a complex of valuable properties of silicon-organic polymers, mainly by their high heat, resistance to cold and moisture, small changes in physical characteristics in a wide temperature range, and perfect dielectric properties. Polyorganosiloxane compounds with improved physico-mechanical properties are presented. The possibility of changing the properties of adhesive sealants by introducing them into the composition of new modifying additions, structure-forming additions (QM-resins), curing accelerators, and coupling agents has been shown. The elaborated compounds can be recommended for sealing semiconductor devices and integral schemes. The following silicon-organic rubbers were selected as polydimethyloxane rubber SKTN-G and low-molecular polystyrene blockcopolymer «Silest». The derivatives of phenyltriorgan (phenyltriethoxy(methoxy)silane PhSi(OR)3) Mod-1, Mod-5, Mod-3, and Mod-4 served as sealing agents and served as the vulcanization accelerator. The component ratio of the vulcanized system was 1:1; which yielded a complete reaction process and, result compounds, with a wide spread spatial network. These compounds posses high physico-mechanical properties, which was the problem and the aim of the present study. The sealing agents in the system of silicon-organic compounds not only serve as curing agents, but are also chemical reagents in the structure-forming processes that occur by the polycondensation mechanism. Sample tests on determining the elongation during rupture (εr) and the conventional strength during stretching (σr) were performed according to the State Standard 270–75. The values of the vitality and physico-mechanical properties of the elaborated compounds based on SKTN-G (SilON) rubber are as follows: the maximal vitality value was 14 h, the conventional strength during rupture was 4.0–4.3 MPa, and the elongation during rupture was 130–140%. It is important to note that at the same time the curing temperature of the sealant compounds decreased to 75°C. In this way, the work on increasing physico-mechanical parameters while maintaining the elasticity of the elaborated sealant materials was performed. The aim was achieved by introducing new modifying additions, structure-forming additions, QM-resins, curing accelerators, and sealing agents based on phenyltriorganosilanes PhSi(OR)3 into the elaborated compounds based on liquid low-molecular siloxane rubbers and blockcopolymers with improved physico-mechanical properties, including increased conventional strength (4–6 MPa) with preserved elasticity (elongation 150–200%). The formulas of a caulking compound based on polydimethylsiloxane - α,ω-diol (SKTN-G) have been elaborated. Silicon-organic elastomer contains QM-oligomers as the modifier. Increasing the content of QM-resin from 4 to 12.5 wt % leads to increased vitality of the compounds (from 20 to 40 min). The additional introduction of curing inhibitor (naphtylenediamine ND-8) into the compound containing 12.5 pts wt of QM-resin allows increase vitality of the compounds from 40 to 90 min. The elaborated adhesive sealant samples can be recommended for use in electronic devices as sealant materials. By varying the type and ratios of the initial oligosiloxanes and using new sealing agents and other ingredients, one can solve almost any problem posed by different branches of technology in the spheres of application of these materials. In this way, the use of a new structure forming agent, QM-siloxane, allows one to obtain initially fluid compounds that possess transparency, high strength, and elasticity in the vulcanized state. In conclusion, it is necessary to note that the elaborated and researched compounds, which possess a high degree of purity, low internal stresses, and high electrical insulating properties, can be recommended for sealing radio-, electronic, and medical devices.
P-169 NEW COPOLYAMIDES WITH ANTHRAZOLINE UNITS: SYNTHESIS AND PROPERTIES
I.V. Podeshvo1, M.Ya. Goikhman2, R.Yu. Smyslov1, I.V. Gofman1, N.L. Loretsyan1,
A.V. Yakimansky1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004
Russia 2 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, Bolshoi pr. 31, St. Petersburg, 199004
Russia; St. Petersburg State University, Institute of Chemistry, Universitetskii pr. 26, Petrodvorets, St. Petersburg, 198504 Russia
Polymers with anthrazoline units in the main chain possess good mechanical properties, high thermal stability, and are of interest for the preparation of polymer luminophores and semiconductors. Such polymers are usually synthesized by Friedlaender reaction between 4,6-diamino-isophthalic aldehyde with 1,4-bis(phenylacetyl)benzene. The mentioned reaction requires using costly initial reagents, and, moreover, resulting polymers often have rather low molecular weights. We developed a new method of the synthesis of these polymers, employing anthrazoline-containing diamines. To this aim, bis-isatin (benzodipyrrol-tetraone (I)) was prepared via Sandmeyer reaction from m-phenylenediamine, and 2,8-bis(4-aminophenyl)pyrido[3,2-g]quinoline-4,6-dicarboxylic acid II was obtained via Pfitzinger reaction of I with 4-amino-acetophenone. Decarboxylation of II at 300°C in the presence of metallic copper afforded 4,4’-(pyrido[3,2-g]quinoline-2,8-diyl)diamine III.
Based on diamines II and III, polyamides IV and V with the content of anthrazoline units 5, 20, 40 and 60% were synthesized by the method of low-temperature polycondensation.
O
O-CH3
O CO CO
H3C-O
COOC
NN
NH
NH
COOHCOOH
n
m
O
O-CH3
O CO CO
H3C-O
COOCNH
ONH
n = 5, 20%IV
O
O-CH3
O CO CO
H3C-O
COOC
NN
NH
NH n
m
O
O-CH3
O CO CO
H3C-O
COOCNH
ONH
n = 5, 20, 40, 60%V
It is shown that the synthesized copolymers possess a high intrinsic viscosity [η] = 1.0-1.8 dL/g, increasing with an increase in the content of anthrazoline-containing units. The performed investigations of photoluminescent properties revealed that luminescence is virtually absent in polymers based on diamine II, while polymers on the basis of diamine III display a considerable luminescence in the range 580-600 nm, its intensity growing up with a rise in the concentration of anthrazoline-containing units.
NH
NH
OO
O O NH2OCCH3
NN
NH2NH2
COOHCOOH
NN
NH2NH2
+ 2
Cu, T=3000C
I II
III
400 500 600 7000
300
600
900
1200
Iлюм
, пр.ед.
1
2
3
4
1. 5:952. 20:803. 40:604. 60:40
,нм
P-170 SYNTHESIS AND PROPERTIES POLYPHENYLQUINOLINES CONTAINING CARBAZOLE AND INDOLO[3,2-B]CARBAZOLE MOIETY
AND THEIR COMPOSITIONS WITH 2,1,3-BENZOTHIADIAZOLE
N.V. Matyushina1, V.M. Svetlichnyi1, L.A. Miagkova1, E.N. Popova1, I.V. Gofman1, E.L. Aleksandrova2, A.R. Tameev3, V.V. Kudryavtsev1
1 - Institute of Macromolecular Compounds Russian Academy of Sciences, 199004, St. Petersburg, Russia 2 - A.F.Ioffe Physical Technical Institute Russian Academy of Sciences, 194021, St. Petersburg, Russia
3 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of Sciences, 119071, Moscow, Russia
By Friedlaender reaction of di-ortho-amino ketones with different bridging groups (phenylamino or oxygen) and diacetyl derivative carbazole and indolo[3,2-b]carbazole with N-alkyl substituents of varying length, was synthesized a number of polyphenylquinolines (PPQ) of the general formula:
N
X
N Ar n , wherein X =-O-; = N-Ph
N
N
R
R
N
R
Ar = ;
R = C8H17-; C12H25-; C18H37- Molecular weights of synthesized PPQ with phenylamino bridging group were 5000-50000 depending on the arylene fragment and for PPQ with oxygen bridging group – 45000-135000. According to thermogravimetric analysis the temperature (τ5) of synthesized polymers is 420-500ºC. The self-supporting films were prepared based on polyphenylquinolines with an oxygen bridging group (the modulus of elasticity (E) of 2.2-3.2 GPa, tensile strength at break (σbr) of 90-130 MPa and elongation at break (εbr) 4-18 %). It was shown that the photosensitive properties PPQ (sensitivity S0.1
I and quantum yield of photogeneration of charge carriers η) increase when replacing from the oxygen bridging group to phenylamine (η increases in 2-5 times), and under identical bridging groups η is increased by 2 times at the transition from carbazole arylene moiety to indolocarbazole. In order to improve the photophysical properties of the synthesized PPQ were prepared polymer composition with the addition of 10 weight percent 2,1,3-benzothiadiazole (BTDZ). It was shown that the sensitization of the photoelectric effect in compositions of polyphenylquinolines with acceptor molecules BTDZ is quite effective: the introduction of the BTDZ leads to a broadening of the spectral sensitivity range and increasing the integral sensitivity S0.1
I in 4.5 times, and the photocurrent (photoconductivity phenomenon) – more than 6 times. This work was supported by the Russian Foundation for Basic Research (project 14-03-01137_a).
P-171 STRUCTURE AND ELECTROCHEMICAL PROPERTIES OF NEW POLYANILINE - POLYACRYLAMIDE HYDROGEL COMPOSITES
I.Yu. Dmitriev, P.V. Vlasov, M.A. Smirnov, G.K. Elyashevich
Institute of Macromolecular Compounds, Russian Academy of Sciences [email protected]
Composites based on electroconductive polymers are perspective types of electrode materials for electrochemical energy storage devices (supercapacitors) which attracted considerable attention in the recent years. In this work the electroactive composite systems consisting of polyaniline particles (PANI) in the volume of the elastic crosslinked polyacrylamide (PAAm) hydrogel were investigated. A new method of the composite preparation has been elaborated. PANI synthesis was carried out in the solution of linear PAAm, and then PAAm was crosslinked with acetone. Structure and electrochemical properties of the composites were studied. It was established that the composite systems prepared by this method demonstrate mixed type of conductivity (electronic and ionic charge transfer, both) due to the continuity of polyaniline phase inside the sample. The synthesized composites are evaluated as active electrode materials for supercapacitor applications. The galvanostatic charge/discharge experiments demonstrate that these materials have a high specific capacitance (130F/g) and good cycle stability. It is shown that PANI/PAAm electrodes are characterized by a broad parallelogram shaped peak on cyclic voltammetric curves which is an evidence of the pseudo capacitive behavior. Good mechanical properties and low charge transfer resistance suggest that the prepared composites may be considered as promising electrode materials for energy storage devices with high performance. This work was supported by the Russian Foundation of Basic Research (Grants № 13-03-00219 and № 14-03-31411).
P-172 SORPTION OF BIVALENT METALS IONS BY POLYACRYLATE SODIUM AND POLYACRILIC ACID HYDROGELS
Z.F. Zoolshoev, N.G. Belnikevich, N.V. Bobrova, G.K. Elyashevich
IMC RAS, St.Petersburg, Russia [email protected]
Polymeric hydrogels based on the cross-linked acrylic acid (PAA) and its derivatives attract a great interest from the scientific and practical points of view due to a high degree of swelling in water and pH-sensitivity in a wide range of acidity of a medium. In recent years polyelectrolytic hydrogels have been widely used as sanitary and hygienic cosmetics, and also for the treatment of waste water, in melioration, etc. The goal of this work was the comparative investigation of PAA and polyacrylate sodium (PAA Na+) hydrogels, obtained by free radical copolymerization with N, N' - methylenebisacrylamide as crosslinking agent. PAA Na+ hydrogels were prepared by copolymerization in aqueous solution with redox system of ammonium persulfate-tetramethylenediamine as initiator. Acrylic acid was neutralized by sodium hydroxide. PAA gels were synthesized using of ammonium persulfate-sodium sulfite-Mohr's salt as initiator. Ratio of initiator /monomer was 1/1000. The monomer concentration in both syntheses was 25 %. Equilibrium swelling degrees of gels (Qeq) in dependence on pH were measured. For PAA gels, Qeq increases with pH and reaches a maximum value equal 250 at the highest pH = 11.5. PAA Na+ gels had the maximum value Qeq = 200 at pH = 6. Sorption of the PAA Na+ and PAA gels in the salts of bivalent metals solutions was studied. The dependence of the amount of metal ions fixed by the gel on ions concentration of initial solution was observed. It was found that the higher a concentration of salt solution, the more an amount of metal ions are bounded by the hydrogel. The maximal sorption was observed for the system PAA Na+-CuSO4 where 1 g-mol PAA Na+ sorbed 0.7 g-mol CuSO4. At the same time 1 g-mol of PAA hydrogel absorbed only 0.17 g-mol CuSO4, i.e. in 4 times less. It was shown that adsorption capacity of PAA gel weakly depends on crosslinking degree in the range from 75 to 300 monomer units between crosslinks. The amount of sorbed salt was 0.1 to 0.2 g-mol per 1 g-mol PAA gel. It should be noted that the gel may be regenerated: sorbed metal ions are completely removed at swelling of gel in 0.1N hydrochloric acid. The work was supported by Russian Foundation of Basic Research (Grant № 13-03-00219-a).
P-173 NEW METHOD OF CREATION OF POLYMERIC BLENDS WITH FLEXIBLE BIOCOMPATIBLE POLYMERS
E.G. Rukhlya, L.M. Yarysheva, A.L. Volynskii, N.F. Bakeev
Lomonosov Moscow State University [email protected]
Cold drawing of amorphous glassy polymers in the presence of adsorptionally active liquid media (AALM) proceeds via the nucleation and growth of the local deformation regions referred to as crazes, and the whole process has been coined as solvent crazing. This specific mode of the plastic deformation of polymers involves stress-induced disintegration of the polymer material in crazes into fine aggregates composed of oriented macromolecules (craze fibrils), which are spaced by voids (pores) of the same dimensions. To summarize, solvent crazing involves the development of a highly dispersed fibrillar — porous structure with dimensions of pores and craze fibrils of about 2—20 nm, and crazing by itself can be treated as a universal method for the development of the nanoscale porosity. It is important to mention that parameters of the resultant porous materials such as porosity, specific surface, and pore dimensions, can be easily controlled by varying conditions of tensile drawing (tensile strain, temperature, strain rate, geometry of the sample, etc.). The phenomenon of solvent crazing can be used for the preparation of diverse composites with the nanoscale level of dispersion between the components, and this factor is controlled by the parameters of the specific fibrillar — porous structure of the crazes. When drawing is carried out in a solution that contains various flexible high-molecular-mass compounds (from oligomers to polymers with m.m. more then 1 mln), these compounds can effectively penetrate into the porous structure of craze. As a result, it becomes possible to manufacture polymer-polymer blends which structure is like structure of interpenetrating networks in which both polymer and incorporated polymers are dispersed at the nanometer scale. This method allows to prepare a blends based on thermodynamic incompatibility polymers which components unfeasible to mixing via in melt or solution. Tensile drawing of the poly(ethylene terephthalate) (PET) samples in semidilute solutions of poly(ethylene oxide) (PEO) with the molecular mass ranging from 4 103 to 1 106 proceeds via the mechanism of solvent crazing. This process is accompanied by the penetration of PEO into the porous structure of crazes, and this conclusion is proved by the data on the composition of the resultant blends as well as by the direct electron microscopic observations. Penetration of PEO into the solvent-crazed nanoporous structure proceeds under so-called “confined” conditions when the hydrodynamic radius of a polymer coil is comparable or higher than the effective dimensions of pores in the crazes. Penetration of the PEO macromolecules into the porous structure of the solvent-crazed PET-based sample via diffusion under the action of the concentration gradient is compared with the flow-assisted penetration in the course of the tensile drawing of the PET samples in the PEO solutions. The PEO content in the pores of the solvent-crazed polymer is controlled by the overall porosity of the parent polymer as well as by the concentration of the feed polymer in the surrounding solution. Content of PEO in the pores of the solvent-crazed polymer samples is higher than that in the surrounding solution, and this fact can be explained by the adsorption of PEO on the highly developed surface of the fibrillated polymer in crazes. Penetration of PEO into the porous structure upon tensile drawing proceeds much quicker (minutes) as compared with the attainment of the equilibrium content of the polymer under the action of the concentration gradient (days). Comprehensive studies on the specific features of solvent crazing of polymers in the solutions of high-molecular-mass compounds are performed, the mechanism of penetration of macromolecules into the nanoporous structure of crazes is established, and structure and properties of the prepared blends are characterized. This work was supported by the Russian Foundation for Basic Research. Project No. 12-03-00338-а), by the Grant of the State Support of the Leading Scientific Schools, NSh-1683.2014.3.
P-174 STRUCTURE OF ORGANOSILICON POLYMERS WITH LINEAR AND CYCLIC FLUORINATED SUBSTITUENTS
T.S. Lyubova1, K.V. Sidorenko2, Yu.P. Klapshin3, V.V. Semenov1, O.V. Kuznetsova1,
E.Yu. Ladilina1 1 - Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences
2 - Research Physico-Technical Institute, Lobachevsky Nizhegorodsky State University 3 - Lobachevsky Nizhegorodsky State University
The hydrolysis of trifunctional alkoxysilanes RFOCH2Si(ORF)3, where RF = CH2CF3 (1), CH2CF2CF3 (2), CH2CF2CF2CF3 (3), or CH2CF2CF2CF2CF3 (4), during the action of atmospheric moisture in the presence of 3-aminopropyltriethoxysilane (APTES)under mild conditions yields ladderlike polysiloxanes. The hydrolysis of compositions formed from APTES and new monomer 2,2-diethoxy-7,7-bis(trifluoromethyl)-1,6,2-oxazasilepane (5) yield mainly cross-linked polysiloxanes by the same conditions. The powder XRD study shows that polymers from alkoxysilanes 1–4 have layer structure. The positioning of polysiloxane polymer chains in the plane (in a single layer) is specific ordering with the participation of organofluorine substituents: there is the interchain electrostatic interaction between CF3 end group electron-rich fluorine atoms and electropositive silicon atoms belonging to neighboring polymer chain. It results in a polymeric network formation. A polymers from alkoxysilane 5 have partly ordered structure. Their IR spectra show the absorption bands of stretching vibrations of the N—H bonds of coordinated amine. The nitrogen atom interact with the silicon atom of fluorinated monomers:
OO
NH2
Si
O
O
C
OSi
HNF3C
F3C
O Si OO
NH2
O
C
O
NH CF3
CF3
Si
The d-spasing of the relatively regular structure of polymers from alkoxysilanes 1–5 is increased by the size of the organic substitutive groups on silicon. The structure of polymers is studied via 1H NMR spectroscopy, GPC, TGA, powder XRD and AFM. All coatings prepared from compounds 1–5 are very smooth: Ra is as low as 0.5 nm. Thin-films coatings based on these polysiloxanes are hydrophobic, low-energy. An increase in the hydrophobicity of the surface of coatings and a decrease in their total surface energy observed with an increase the content of fluorine in the films. Absorption bands in UV, visible, and near IR region are not observed for the obtained polysiloxane. Ellipsometric measurements show that polymer has low refractive index over a wide wavelength range. The minimum value for the sample achieves 1.300–1.305. A polymers from alkoxysilane 5 have a high pencil hardness (9H). Owing to their easy synthesis via hydrolysis under mild conditions in the presence of atmospheric moisture, coatings can be prepared directly on substrates without any further heat treatment. This fact is especially important for the formation of protective coatings for high-aperture nonlinear optical elements based on lithium iodate crystals used in high-power laser apparatuses. This work was financially supported by the Russian Foundation for Basic research (Project 14-03-31103 мол_а)
P-175 MOLECULAR MOBILITY IN SPECIALLY ARRANGED SILOXANEURETHANE NETWORKS
N.S. Perov1, E.S. Obolonkova1, L.I. Makarova2, N.V. Sergienko2, A.N. Ozerin1
1 - Enikolopov Institute of Synthetic Polymeric Materials, Russian Academy of Sciences 2 - Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences
Ever-increasing level of sophistication of multicomponent polymer systems today has led to a situation where the newly created objects became characterized only by some spectrum of the molecular mobility of the system "as a whole". At the same time a number of important structural and dynamic factors influencing to the relaxation spectra of complicated polymer systems were ignored or droped out from the consideration. The main purpose of this work was to study the mechanism and molecular mobility peculiarities of interpenetrating (IPN) and semi-interpenetrating (SIPN) siloxaneurethane networks with polymethylmethacrylate (PMMA) and model organosiloxaneurethane block copolymer structure networks. It is shown that the determining factor of molecular mobility in siloxaneurethane systems is the presence of PSU components in their structure. Urethane groups determine the nature of the interaction between PMMA and PSU. Fundamentally important in such systems is the ability to control the level of molecular mobility when siloxane units has not sufficient length and phase separation has not occurred. In these cases, the interaction of the polar groups of PMMA and PSU limits the mobility of the grid nodes. It was shown that under certain PMMA-PSU rations SIPN the displacement occurs of PSU low-temperature transition in amounts 5 - 12 degrees to lower temperatures relatively PSU networks without PMMA. At the same time in the PMMA-PSU IPN such a shift was not found. It is suggested, that the polar groups PMMA can block the intermolecular urethane group interactions between neighboring macrochains. An analysis of positions and shapes of the low-temperature relaxation peaks for organosiloxaneurethane copolymers demonstrates that the low-temperature relaxation mechanism does determine by large-scale mobility of linear organosilicon fragments and may include the organosilicon junction fragments as the kinetic element. The phenomenological model of a molecular mobility is offered for such systems. It is based on the assumption that the influence on a molecular mobility takes place through the local topological obstacles and chemical bonds.
P-176 IMPACT OF DIFFERENT NANOPARTICLES INTRODUCED INTO THE AROMATIC POLYIMIDE MATRICES UPON DENSITY VALUES OF
THE MATERIALS
I. Abalov, I. Gofman, E. Popova, V. Smirnova, V. Yudin Institute of Macromolecular compounds RAS, St.-Petersburg, Russia
The experimental density values were determined of several nanocomposite materials obtained by the introduction of different nanoparticles into the matrices of some aromatic polyimides (PIs). These values were compared to those calculated using the additive scheme: composite = polymerCpolymer+nanoCnano, where polymer and nano denote the densities of the nanocomposite’s components, Cpolymer and Cnano denote the concentrations of these components in the composite material, in vol. %.
2 4 6 8 10 12
1.01
1.02
1.03
1.04
1.05
/0
C nano, vol.%
PMDA-ODA+ carbon nanocones
experiment calculation
2 4 6 8 10
1.01
1.02
1.03
1.04
1.05
1.06
C nano, vol.%
PMDA-ODA+ nanoclay
experiment calculation
/0
1 2 3 4 5
1.01
1.02
1.03
1.04
C nano, vol.%
PMDA-ODA+ hydrosilicate nanotubes
experiment calculation
/0
2 4 6 8
1.01
1.02
1.03
1.04
/0
C nano, vol.%
- R-BAPB+ carbon nanofibers (experiment) - R-BAPB+ carbon nanocones (experiment) - R-BAPB+ carbon nanoparticles (calculation)
Fig. 1. Experimental and calculated density values of some nanocomposite films vs. the nanofiller’s concentration. For all nanocomposite films tested the experimental values of density were found to be slightly inferior to the calculated ones. In all cases the introduction of some nanofiller into the PI matrix leads to the generation of some excessive free volume in the material. The amount of this excessive free volume is practically the same for all nanocomposite films tested. For example, the experimental densities of all nanocomposite films presented in Fig. 1 are as high as 0.9960.002 of the calculated densities if the concentration of a nanofiler in the composite film is 3 vol. %. The formation of bulky PI-based nanocomposite materials leads to a generation of more substantial excessive free volume: for the same concentrations of hydrosilicate nanotubes (halloysite), carbon nanofibers or nanocones/discs (3 vol. %), introduced into the polyimide Ultem the experimental density values of the materials obtained are of 0.9820.002 of the calculated density values. Acknowledgements The work is supported by Russian Foundation for Basic Research (project No. 13- 03- 00547).
P-177 COEFFICIENTS OF THERMAL EXPANSION OF PI-BASED NANOCOMPOSITE FILMS CONTAINING DIFFERENT TYPES OF
NANOPARTICLES
I. Gofman, S. Lyulin, S. Larin, V. Yudin Institute of Macromolecular compounds RAS, St.-Petersburg, Russia
The experimental values of linear coefficient of thermal expansion (CTE) were determined in a wide range of temperatures (from RT up to 200 OC) of several bulky nanocomposite materials obtained by the introduction of different nanoparticles into the commercially available thermoplastic polyimide Ultem-1000 (Sabic Co). The following types of nanoparticles were used as active fillers: carbon nanofibers (VGCF), carbon nanocones/discs (CNC), natural halloysite nanotubes, and zirconium dioxide doper with yttrium oxide. The spherical nanoparticles of ZrO2-Y2O3 were used in the concentration of ~2 vol.%, and all other nanofillers were introduced into the matrix polymer in the concentrations of 3 vol. %.
20 40 60 80 100 120 140 160 180 200 2202.0x10-5
4.0x10-5
6.0x10-5
8.0x10-5
1.0x10-4
1.2x10-4
1.4x10-4
1.6x10-4
T, OC
- Ultem - Ultem+carbon nanocones (3 vol.%) - Ultem+carbon nanofibers (3 vol.%) - Ultem+halloysite (3 vol.%) - Ultem+ZrO
2-Y
2O
3 (2 vol.%)
CTE,1/deg
Fig. 1. CTE values of several bulky Ultem-based nanocomposite materials vs. temperature. The introduction of all types of nanoparticles used into the Ultem matrix leads to a depression of the CTE values of the material. This tendency can be clearly seen in the temperature range from RT up to ~ 180 OC. The most modest decrease of CTE (up to 0.82-0.85 of the CTE value of Ultem samples in the temperature range from RT to 100 OC) was registered at nanocomposite samples filled by halloysite and ZrO2-Y2O3. The most pronounced effect of the CTE depression was registered while the Ultem-CNC samples were tested: the mean CTE value of this composite in the temperature range from RT to 100 OC was of ~ 0.57 of that of the unfilled Ultem samples. The correlations are discussed of the CTE value and amount of free volume in the nanocomposite materials studied. Acknowledgements Acknowledgement is made to Dr. A. Bugrov (IMC RAS) who has synthesized the ZrO2-Y2O3 nanoparticles. The financial support provided by Russian Foundation for Basic Research (project No. 13- 03- 00547) is acknowledged.
P-178 NON-LINEAR OPTICAL AND PHOTOSENSITIVE PROPERTIES OF CHROMOPHOR-CONTAINING POLYIMIDES
N.N. Smirnov1, N.A. Solovskaya1, G.I. Nosova1, A.V. Yakimansky1, I.G. Abramov2,
O.V. Dobrokhotov2, E.L. Aleksandrova3 1 - Institute of Macromolecular Compounds Russian Academy of Sciences, Saint-Petersburg, Russia
2 - Yaroslavl State Technical University, Yaroslavl, Russia 3 - Ioffe Physicotechnical Institute, Russian Academy of Sciences, Saint-Petersburg, Russia
Non-linear optic (NLO) materials are of great interest for optoelectronics. They make it possible to change the frequency of light passing through them and to realize a communication between electric and optic signals via a laser light-perturbed electronic distribution in the material. Polymer NLO materials present additional advantages for applications in optoelectronic systems of the information recording, storage, and processing, since their structure may be widely varied and properties finely tuned. In the present paper, for the creation of materials, possessing both photoconductivity and electrooptic response properties, thermally stable polyimides (PI) with covalently attached chromophore groups were synthesized and investigated.
CH2
HO OH
N Q N
O
OO
O
TPP ROH
CH2
HO O
R
N Q N
O
OO
O
n
n
EADC
ON
N
CNCN
N
HO
NN
CNCN
N
OH
R3 R4
N
O
CN
CN
R1
N
CN
CN
HO
R2
HO
The chromophores differed in the position of electron-acceptor nitrile groups. Some of the chromophores contained bulky substituents, preventing aggregation of chromophore moieties. The degree of substitution of chromophore for phenol groups was 40-50%. Film samples with the thickness 0.1-2.0 m were corona-poled at the voltage 4-6.5 kV and the temperature 150-200°C for 40-60 min. Non-linear optical properties were studied by the second harmonics generation method with the use of a pulse YAG Nd3+ laser (the fundamental wavelength 1064 nm). A number of the obtained polyimides demonstrated a high macroscopic quadratic nonlinearity (d33~30 pm/V, in some cases ~70 pm/V). Photosensitive properties of the synthesized polymers characterized by their photosensitivity (S0.1) measured with the use of the electrophotographic method were also studied. Investigations of the charge carriers photogeneration process by this method showed that chromophore groups introduced into the considered polymers enhanced their photosensitivity by a factor of 3-7 compared to the initial chromophore-free polyimides. For the most of the studied polymers, their spectral photosensitivity is 5÷8×104 cm2/J, while for the polyimide based on bis-(2-aminohydroxyphenyl)methane and 4,4-(4’,4’-isopropyliden-phenoxy)-bis(phthalic anhydride), containing electron-donor carbazole fragments (R4), rather high NLO properties (d33 = 54 pm/V) are combined with a maximal integral photosensitivity at the level of 2.5×10-2 (lux×s)-1 in the range 400-570 nm. The work is supported by the Russian Foundation for Basic Research (project no. 12-03-00709-а).
P-179 HYBRID COMPOSITE MATERIALS BASED ON HETEROCYCLIC AND SILICONE POLYMERS
V.M. Svetlichnyi1, V.E. Yudin1, L.A. Miagkova1, E.N. Popova1, N.N. Saprykina1, V.E. Smirnova1,
V.Yu. Elokhovskii1, I.V. Gofman1, E.N. Vlasova1, E.A. Tatarinova2, I.B. Meshkov2 1 - Institute of Macromolecular Compounds of the Russian Academy of Sciences, St.Petersburg, Russia
2 - Enikolopov Institute of Synthetic Polymeric Materials, a foundation of the Russian Academy of Sciences, Moscow, Russia
Hybrid compositions, based on the number of synthesized polyimides ( PI ), and MQ- silicone resins were prepared by thermal curing of polyimide prepolymers and organosilicon resins. Samples of the new hybrid PI -MQ polymer systems containing up to 60-70 wt. % silicone component were synthesized and physical and mechanical properties were evaluated : E = 07-2,5 GPa, σbr = 50-142 MPa, εbr = 20 - 44 %. Hybrid polymers exhibit a high level of heat resistance in argon ( 5 = 450 ÷ 550°C) and ( 5 = 440 ÷ 510°C) in air. The compatibility of the imide and silicone component in the melt were investigated by rheology method , and in the solid state by electron ( SEM), infrared spectroscopy and dynamic mechanical analysis. The study was supported by the Russian Foundation for Basic Research (grant No. 13-03-12111-ofi-m).
P-180 PATENTS OF THE ASIAN-PACIFIC REGION IN INFORMATIONAL SUPPORT FOR ACADEMIC RESEARCH INSTITUTE
E.N. Stavinsky, M.S. Romanova
Institute of Macromolecular Compounds of the Russian Academy of Sciences, Saint-Petersburg, Russia [email protected]
For last ten years the countries of Asian-Pacific region are considered as recognized leaders in Science. Japan, China and South Korea appear to be particularly promising, that’s why the patent information of these countries is very required. The information retrieval and analysis of Japanese and Chinese patent applications on “Polyimide membranes” as high technology subject for 2012-2013 years are carried out. Two problems are examined: a) a ratio of Japanese and Chinese patent applications in total patents on the subject; b) language accessibility of Japanese and Chinese patents. Espacenet patent database containing abstracts and full texts of the patents has been used. As a result, 228 documents were selected. The priority country distribution is as follows: China (71), Japan (36), USA (29), South Korea (22), Taiwan (2). Only 17 documents (about 13%) from a total amount (131) of China, Japan, USA, South Korea, Taiwan are published also in English (as ET or US patents). All patents in Espacenet have abstracts in English. How much the abstracts of the Japanese and Chinese patents are satisfied to the specialists without the acquaintance with full texts? A content analysis shows that Espacenet abstracts of the Japanese and Chinese patents can be defined as indicative abstract or annotation, which means that a specialist cannot do without full patent text including description. Improving of providing the academic institute researches with the achievements claimed in Japanese and Chinese patents can be realized by paten and information service specialists by means of retrieving, translation and composing enlarged abstracts containing important information units defining patent as juridical and scientific-technical document: claims, examples, citation, properties, tables, test methods and others. Such work is hard and needs a high qualification including knowledge of Japanese language and patent branch. However, the academic institute activity cannot be successful without effective information service. It is impossible to ignore here Japan and China. Economies on information can lead to unjustified expenses of human and financial resources to carry out noncompetitive research and development. We hope that composing the enlarged abstracts of Japanese and Chinese patents, systematization and analysis of important information included in them is capable to avoid above mentioned risks. Revival of information services and offices which have been unfortunately destroyed in Russian Academy of sciences can become a great help in this matter.
P-181 CHARACTERIZATION OF MORPHOLOGY OF PP FILMS FILLED WITH CARBON NANOFIBERS BY MEANS OF OPTICAL
SPECTROSCOPY
V.E. Sitnikova1, S.D. Khizhnyak1, O.A. Moskaluk2, E.S. Tsobkallo3, V.E. Yudin2, P.M. Pakhomov1 1 - Tver State University, Tver, Russia
2 - Institute of Macromolecular Compounds RAS, St.Petersburg, Russia 3 - St.Petersburg Polytechnical University, St.Prtersburg, Russia
Nowadays production of various polymeric materials such as composites, blends grows rapidly. To fabricate the polymeric materials with definite properties (mechanic, thermo-, electro- and others), particles of organic or non-organic fillers are introduced into the polymer matrix. It is very important to obtain the uniform distributions of the filler particles in the polymeric materials or in some cases – distributions of the particles by a special way, and to avoid the particles aggregation. Filler particle size and shape, distribution in polymer bulk has an essential effect on properties of the final material. Therefore, development of various experimental methods for characterization of the structure of the polymer composites and functional materials is of great importance. A novel spectroscopic approach for estimation filler particle distributions and average particle size has been developed [1; 2] and successfully applied for different types of analyzed samples [1; 2]. In this work an attempt to use the spectroscopic technique for characterization of orientation of the filler particles in the polymeric material is performed. For the study polypropylene films filled with different concentration (5, 10, 15 and 20%) of anisotropic particles of carbon nanofibers (CNF) of about 5 µm length and diameter of ~150 nm are chosen. The composite samples are prepared through the melt in twin-screw laboratory extrusion machine «DSM Explore 5 ml».
8000 7000 6000 5000 4000 3000 2000 1000 00
10
20
30
40
3
2
1
Tra
nsm
itta
nce
, %
Wavenumber, cm-1
0 5 10 15 20 25
0.00
0.01
0.02
0.03
0.04
0.05
3
2
1
d, m
dS/d
FTIR spectra of PP - CNF (5%) film recorded at different positions toward the incident radiation (1 – 0º, 2 – 45º, 3 – 60º) and corresponding particle size distributions
To estimate the orientation of the CNF particles in the PP matrix IR spectra of the composite films are recorded on a FTIR spectrometer «Vertex 70” («Bruker») at 12 different positions of a sample toward the incident radiation (Figure). Particle size distribution and orientation of the carbon nanofibers are evaluated from the spectroscopic data according to the calculation procedure presented in [3]. Images of the samples are obtained on scanning electron microscope (SEM) «Supra-55" («Carl Zeiss»). It is found out that the average particle size in the PP films is changed under rotation of the sample toward the incident beam, that are evidences of anisometry of CNF particles and their preferable orientation of ~ 60 º to the direction of extrusion of the composite films. References [1] Khizhnyak S.D., Malanin M.N., Eichhorn K.-J. Pakhomov P.M. // Vysokomolek. soed. 2008 B. V50, N6. P.1116-1123. [2] Sitnikova V.E., Khizhnyak S.D., Pakhomov P.M. // European Researcher. 2013. V 63, N 11-2. Р. 2666–2674. [3] Pakhomov P.M., Malanin M.N., Khizhnyak S.D. // Vysokomolek. soed. 2008. V50 N6B. P. 1113–1115.
P-182 VALUATION OF KNOW-HOW OF RAS RESEARCH INSTITUTES
I.S. Sitnikova, M.S. Romanova Institute of Macromolecular Compounds of the Russian Academy of Sciences, Saint-Petersburg, Russia
In accordance with Federal Law 217, institutes of Russian Academy of Sciences (RAS) are permitted to establish small innovative business enterprises (SIBE) based on the results of intellectual activity (RIA) obtained in the process of performing fundamental research scientific work (RSW) at the expense of budgetary funds. Specially created RIA Protection Commissions should assist RAS employees in starting these businesses; they have the right to register and valuate know-how with value not exceeding 10 000 rubles without enlisting the services of licensed valuers. Thus, this permission facilitates fast registration of the registered know-hows as intangible assets in accounting in RAS institutes and serves as a basis for calculation of license cost or share in charter capital of SIBE. As a rule, RIA Protection Commission values know-how at no more than 10 000 rubles, if the prospects of an innovation on the market are difficult to forecast. In this case, charter capital of a SIBE organized under the auspices of RAS institute is 10 000 – 15 000 rubles. The expenditures connected with starting business can pay for themselves in 2-3 years if technical implementation of know-how does not require complicated instruments or high expenditures for environmental safety. The method for know-how valuation includes the stage of detection of know-how ready for commercialization on the basis of the institute among all know-hows registered in the institute, the immediate stage of know-how valuation (up to 10 000 rubles), the stage of valuation of the charter capital amount of the new SIBE and the share of the institute in this SIBE accounting for intellectual property. Experience has shown that minimum valuation of know-how is 3500 rubles (35% in the charter capital of SIBE). Another possibility to valuate know-how arises if creation of intellectual property was planned during implementation of state contract and expenditures were included in calendar plan. RIA Protection Commission can settle the stated sum as an official know-how cost which can be presented to potential investors and license buyers. As indicated above, the presented know-how valuation concerns innovations which do not require high expenditures for creation and realization. The practical experience of detection and commercialization of these know-hows has shown that they are no more than 10 percent of RIA created in RAS institutes. However, SIBE based on these know-hows can facilitate accumulation of finances for performing valuation by licensed valuers and commercialization of other (more expensive) new technologies in scientific institutes.
P-183 NATURAL FULLERENE-LIKE MULTIFUNCTIONAL FILLER FOR POLYURETHANES
E.R. Volkova
Institute of Technical Chemistry of Ural Branch of the RAS [email protected]
Shungite is a natural composite comprised of highly dispersive particles of silica (up to 60%) distributed throughout an amorphous carbonic matrix (Fig. 1). It has been ascertained that shungite contains C60 and C70 fullerenes which are active while interact with polar and weakly polar media [1]. Since shungite particles contain carbonic and silicate constituents, they are compatible with polymers of different polarity. In this work, shungite was used as a modifier of polyurethane (PU) composites characterized by isocyanate curing system [2]. Since silanol OH–groups located on surface of SiO2 particles are capable of interacting with NCO–groups of a curing agent and of forming additional chemical bonds between a filler and polyurethane matrix, it may be assumed that shungite is “embedded” into the structure of a polymer. It has been demonstrated by using the FTIR spectroscopy that small (up to 3%) quantities of shungite are capable of catalyzing urethane formation reaction between polyethers and isocyanates. Integrated investigations in rheological and physic-mechanical properties of a PU composite based on a mix of hydroxyl-containing oligomers with polyisocyanate have shown that shungite is multifunctional filler simultaneously playing a role of both plasticizer and reinforcing filler. A PU composite modified with 7% of shungite is featured by an increase in: life time – 1.5-fold; strength value – 1.6-fold; Young modulus – 3.5-fold. Structural variations were registered by using the Raman spectroscopy (Fig. 2). A hike in relative intensity of peaks typical for urethane groups’ carbonyls with strong hydrogen bonds indicates participation of shungite in formation of polymeric structure of a composite with improved operating characteristics.
Figure 1. REM-picture of shungite. The structure of C60 fullerene.
Figure 2. Variations in microstructure of polymeric matrix (a); matrix modified with
shungite (b). Acknowledgements. The work was financially supported by the Russian Foundation for Basic Research (project 14–03–00051) and by Ural Branch of the Russian Academy of Sciences (project 12–T–3–1002). References:
1. P.R. Buseck, S.J. Tsipursky, R. Hettich // Science, 1992 257 (5067) 215. 2. Volkova E.R., Tereshatov V.V., Vnutskikh Zh.A. // Rus. J. of Appl. Chem., 2010 8 (83)
1372.
P-184 THERMODEFORMATIONAL BEHAVIOR OF THE ORIENTED POLYPROPYLENE POROUS FILMS
I.S. Kuryndin, N.N. Saprykina, G.K. Elyashevich
Institute of Macromolecular Compounds, Russian Academy of Sciences, Saint-Petersburg, Russia [email protected]
Deformational stability, behavior of the porous polypropylene (PP) films at heating and changes in porous structure at shrinkage have been investigated. The grades of isotactic PP (Mw = 380000, Mw/Mn = 4-5, Tm = 172 0C) were used to form porous structure in the process based on the polymer melt extrusion, followed by isometric annealing, uniaxial extension at the room temperature (the stage of pore formation), and thermal fixation. The films obtained in this process are characterized by the oriented type of structure. The porous samples contain the through flow channels that provides them permeability for liquids. Sizes of through channels and permeability of the porous films were determined by filtration porosimetry. To avoid the shrinkage and consequently sharp drop of pore sizes the porous samples extended at room temperature should be fixed with keeping at elevated temperature (thermal fixation) to stabilize the porous structure. Being extended they demonstrate the shrinkage ~ 80 % when uniaxial deformation stops. It was established that stabilization of the porous structure may be successfully realized if fixation temperuture (TF) is higher than 110 0С. At TF more than 130 0C rearrangement of the structure and closing of through channels occur because of partial polymer melting process. This result was confirmed by the dependences of permeability of the porous films on TF which has a maximum at TF = 130 0C. The porous samples exhibit shrinkage at heating as result of their oriented structure. The value of shrinkage increases with growing of temperature (TS) because mobility of molecular chains and, as consequence, their ability to relax raises. When TS is close to the melting point of PP the maximum value of shrinkage (60 %) is reached for all porous samples independently of TF (Fig.).
30 70 110 150
15
30
45
60
50
100
150
200
G S
G, l / m2 h atm
S, %
TS, 0C
Fig. Permeability (G) and value of shrinkage (S) dependences on temperature for the porous PP films (TF = 130 0C).
Structure tranformation of the porous films at heating has been investigated by scanning electron microscopy (SEM). The porous samples have a relief-like strongly developed surface. The surface texture is formed by stacks of lamellae and rows of pores between them. It can be seen from SEM images that the distance between stacks of lamellae (area occupied by pores) decreases in result of shrinkage. It was found that the value of shrinkage goes down as TF increasing. It was shown that shrinkage of the films leads to decreasing in their permeability. As shrinkage is growing the pore size distribution shifts to lower values, and the number of through channels is reduced. It was established that the permeability drops to zero when samples shrinkage reaches ~50 %, i.e. through channels are completely closed (Fig.). The work was supported by Russian Foundation of Basic Research (Grant № 13-03-00219-a and 13-03-12071-ofi-m).
P-185 ON THE CONSTRUCTION OF FULLY ATOMISTIC MODELS OF POLYMER NANOCOMPOSITES
P.V. Komarov1, A.A. Gavrilov2, L.V. Zherenkova3, P.G. Khalatur4, A.R. Khokhlov4
1 - Institute of Organoelement Compounds, RAS, Moscow, Russia 2 - M.V. Lomonosov Moscow State University, Moscow, Russia
3 - Tver State University, Tver, Russia 4 - Institute for Advanced Energy Related Nanomaterials, Ulm University, Germany
Computational techniques for modeling of polymer nanocomposites have been emerged rapidly in recent years as an important complement to experiment. The present work is aimed at development of a new methodology for the construction of atomistic models of polymer matrices with different nanofillers. There are four separate stages involved in our methodology, which is based on multiscale simulations. We begin with mapping of initial monomers and nanoparticles of a filler onto coarse-grained representation using a neural-gas algorithm. Then we construct a coarse-grained model of a polymer matrix by using the dissipative particle dynamics (DPD) method to simulate chemical reaction between monomers. The reaction proceeds toward equilibrium until the desired degree of conversion is reached. At the next stage, the reverse mapping of the obtained coarse-grained model is used to restore a fully atomistic representation of a system under study. Finally, the constructed atomistic models are equilibrated through standard molecular dynamics (MD) technique. To check the developed approach, we have evaluated the density, the glass transition temperature, and the thermal expansion coefficient of the cross-linked polymer matrices with and without nanoparticles, depending on the effective conversion and temperature. The reported study was supported by the Supercomputing Center of M.V. Lomonosov Moscow State University.
P-186 MESOSCOPIC SIMULATIONS OF PAN BASED NANOCOMPOSITES
P.V. Komarov1, J.-P. Chen2, Y.-T. Chiu2, V.A. Ivanov3
1 - Tver State University, Tver 170002, Russia 2 - Industrial Technological Research Institute, Hsin-Chu, Taiwan
3 - M.V. Lomonosov Moscow State University, Moscow, Russia [email protected]
Polyacrilonitrile (PAN) is the main class of raw materials for the preparation of precursors for high-tensile carbon fibers. Up to now a large amount of research articles have been appeared, where the effect of adding different fillers into PAN solutions on improvement of mechanical properties of the precursors has been studied. In the present report, we discuss our results of the theoretical study of the influence of the solvent quality (DMSO/water composition), temperature and amount of filler (MWCNT) on the internal structure of PAN based nanocomposites. To understand better the system behavior, we use a mesoscopic simulation model based on the dynamic density functional theory. We have performed mapping of atomistic structures of PAN, DMSO, water and MWCNT on the corresponding coarse-grained representations (linear bead-spring chains, set of beads connected by bonds of high rigidity and spherical particles). All coarse-grained force field parameters have been obtained from the auxiliary atomistic Monte Carlo simulations using PCFF [1] force field. Obtained results clearly show that the distribution of MWCNT in solution becomes homogeneous with increasing of water content in the solvent. At the same time, the increase of water content causes a rise in the number of nuclei of crystalline phase in the polymer matrix. 1. Sun H. // Macromol. 1995. V.28. P.701.; Sun H., Mumby S.J., Maple J.R., Hagler A.T. // J. Am. Chem. Soc. 1994. V.116. P.2978.; Sun H. // J. Comput. Chem. 1994. V.15. P.752.; Sun H. // Macromol. 1995. V.28. P.701.
P-187 INITIATION OF POLYIMIDE CHAINS ORDERING BY GRAPHENE: MOLECULAR DYNAMICS SIMULATIONS
S.G. Falkovich1, S.V. Larin1, A.V. Lyulin2, V.E. Yudin1, S.V. Lyulin1, J.M. Kenny1
1 - Institute of Macromolecular Compounds RAS, St. Petersburg, Russian Federation 2 - Technische Universiteit Eindhoven, Theory of Polymers and Soft Matter Group,Eindhoven, The Netherlands
Using of nanofillers is among the most promising ways to improve properties of polymer-based materials. One of the effects of nanofillers is their ability to initiate crystallization, providing fast appearance of small crystallites, and crystalline nanocomposites are known to be more stable against cracking than non-filled materials with larger crystallites. Experiments show that single-wall carbon nanotubes (SWCNT) and carbon nanofibers with a high degree of graphitization initiate crystallization in the polyimide R-BAPB (consisting of dianhydride R 1,3-bis-3',4-dicarboxyphenoxy-benzene and diamine BAPB 4,4'-bis-4''-aminophenoxy-diphenyl); this crystallization is going twice as fast in the presence of a nanofiber as that initiated by the SWCNT (Yudin et al., Compos. Sci. Technol., 67(5):789, 2007). These two nanofillers have an identical chemical structure, and differ in morphology only. It may be assumed that one of the factors influencing the crystallization rate is the nanofiller surface curvature. To verify this assumption and to investigate the molecular mechanisms of the nanofiller surface-curvature influence on the pre-crystallization process, the atomistic molecular-dynamics simulations have been performed using the Chebyshev and Lomonosov supercomputers of Moscow State University for R-BAPB composites with graphene and the results were compared with those obtained from our previous simulation of R-BAPB composites with SWCNT (Larin et al., RSC Adv., 4(2):830, 2014). A flat graphene sheet and a small-radius SWCNT possess surfaces with extreme curvatures. It was demonstrated that the equilibration time for these materials does not depend practically on a type of nanofiller and the chain mobility is practically the same in both graphene- and SWCNT-filled nanocomposites. At the same time, the nanofiller influences significantly the chain shape; the polyimide chains in composites stretch out as compared to the pure bulk, namely in SWCNT-based composites the R-BAPB chain shape resembles an extended cylinder, whereas in composites with graphene sheet the R-BAPB chains are spread out in the graphene plane. The analysis of the molecular-dynamic trajectories showed that while polyimide chain segments tend to be oriented near the graphene plane, a weaker orientation has been observed at the SWCNT surface. Such orientation can be regarded as the first stage of crystallization near the nanofiller surface. It was also demonstrated that the monomer polyimide near-surface layer density is higher for graphene composite than for SWCNT one. Moreover, this layer is located close to the nanofiller surface for graphene nanocomposite than for SWCNT one. These results confirm the assumption that the nanofiller surface curvature is indeed a factor influencing the polymer structure patterning near the carbon nanofiller surface, smaller curvature provides the enhanced initiation of crystallization. This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002
P-188 STUDY OF THE STRUCTURAL CHARACTERISTICS OF INDIVIDUAL MACROMOLECULES COPOLYMER DISPERSED IN A
MATRIX OF HOMOPOLYMER
A.S. Vishnevskiy, A.E. Chalykh, V.K. Gerasimov Laboratory of Structural and morphological studies IPCE RAS, Moscow, Russia
Modern analytical transmission electron microscopy allows us to observe individual macromolecules dispersed in a matrix of another polymer, and to study their spatial characteristics. The aim of this work was to obtain and study of electron microscopic images of individual macromolecules random styrene-butadiene copolymers (SBR-45) distributed in a matrix of polystyrene (PS), the calculation of their radial distribution functions of the density of segments within the polymer coil, as for individual macromolecules and as the average distribution function for the whole ensemble of macromolecules. Films of polymer blends were obtained by watering of 0.5 wt. % solution in toluene on the water surface at normal conditions. Concentration of SBR-45 in the PS matrix correspond to the infinitely dilute solution and was 0.01 and 0.025 wt. %. Artificial contrast of copolymer were carried in pairs of OsO4 osmium tetroxide according to the standard procedure. Photomicrographs of the studied polymer systems were performed by using a transmission electron microscope EM-301 Philips.
As a result of electron microscopic investigation have been received and processed 240 photomicrographs of individual macromolecules SBR-45 distributed in the matrix of PS. For each macromolecule were identified dimensions and radial distribution functions of density and also radius of gyration, for studied macromolecules radius of gyration ranged from 2.77 nm to 13.84 nm with an average of 6.7 nm. The characteristic form of the calculated curve of the radial distribution functions of density are close to Gaussian curves, the maximum value of the density observed in the center of the coil, and decreases rapidly with increasing distance from the center, reaching almost zero values at the outermost layers. The results are presented
in Fig. 1. From the literature sources it is known that the radial distribution function of the density inside the coil can be described by a Gaussian-like curve (1):
2
2
2
32
3
2)(2
3 g
g
R
R
g
R eR
n
(1)
Where R – radial density distribution function of the polymer molecule, N - the number of monomer units, Rg - radius of gyration of the macromolecule. The figure shows that the calculated and theoretical values are in good agreement. Evaluation of radial distribution functions showed that they do not conflict with previously obtained experimental and theoretical results.
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 5 10 15 20
R, nm
, g/cm3
1
2
Fig. 1. Radial distribution function of the density of segments. 1 – average distribution function which were calculated by processing 240 of electron microscopic images of the macromolecules, 2 – description of the radial distribution function according with the theoretical Gaussian-like curve.
P-189 THE INFLUENCE OF CROSS-LINKER ON COPOLYMERIZATION OF METHYL METHACRYLATE
V.A. Baygildin1, N.A. Lavrov1, N.N. Shevchenko2, G.A. Pankova2, T.G. Evseeva2
1 - Saint-Petersburg State Institute of Technology, Saint-Petersburg, Russia 2 - Institute of Macromolecular Compounds Russian Academy of Science, Saint-Petersburg, Russia
Polymeric particles with narrow size distribution are currently receiving great interest in several application areas such as biomedical studies as carriers of bioligands. One of needed requirements for the particles is a presence of various types of desired functionalities on their surface. The uses of cross-linked PMMA nanoparticles were preferred due to their ability to form stable dispersions in various types of solvents. Copolymerization of methyl methacrylate (MMA), N-vinylformamide (N-VFA) and ethylene glycol dimethacrylate (EGDMA) as a cross-linked agent was explored to synthesize polymeric monodisperse particles. The cross-linker`s influence was investigated on conversion of MMA, shape and particle size distribution as well as surface characteristics of the particles formed. It is shown that the increasing EGDMA concentrations from 0 to 4 wt. % leads to increasing of rate the copolymerization. Molecular weight of formed water-soluble oligomers increases to 2-3 times by adding from 1 to 5 wt. % of cross-linked agent (3600 Да at 0 wt. % EGDMA, 6400 and 10400 Да at 1 и 5 wt. % EGDMA, respectively). The monodisperse spherical particles form only at 5 wt. % EGDMA (Fig. 1,a). One should note here that a particle size curve at various EGDMA concentrations is similar to the Gauss curve with maximum at 2 wt. % EGDMA (Fig. 1,b).
0 1 2 3 4 5250
300
350
400
450
500
550
600
650 particle size obtained by
Dinamic Light Scattering particle size obtained by
Transmission Electron Microscpy
Par
ticle
siz
e, n
m
EGDMA concentratiom, wt. %
(a) (b) Fig. 1. Representative TEM images of cross-linked PMMA nanoparticles (a),
(b) Particle size obtained by Dynamic Light Scattering and Transmission Electron Microscopy
Prepared particles are stability at wide pH-range and inversion of a ζ-potential takes place at alkaline region. This fact says that amino-groups are much more than carboxy-groups on the particle surface. The work is performed at financial support of RFBR (the project № 13-03-00741).
P-190 ADSORPTION OF A PERIODIC HETEROPOLYMER ONTO A PERIODIC CHEMICALLY HETEROGENEOUS SURFACE: A
THEORETICAL STUDY USING A SIMPLE DIRECTED WALK MODEL
A.A. Polotsky Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia and St. Petersburg
National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia [email protected]
Adsorption of heteropolymers - polymers composed of monomer units of two and more types, onto chemically heterogeneous surfaces - was intensively studied in the last decades. A particular interest to this problem is motivated to its connection to the question of molecular recognition, playing a crucial role in living organisms and in various biomedical/biotechnological applications. To understand the mechanisms of the polymer-surface recognition, the problem was extensively investigated from different angles by using relatively simple and physically transparent models. In the present work, adsorption of a periodic heteropolymer onto a periodic heterogeneous surface is studied by using the 2-dimensional partially directed walk model of the polymer. We show how the generating functions approach developed in [1] for the adsorption of a random copolymer onto a random surface can be extended to the case of an arbitrary periodic heteropolymer and a chemically heterogeneous surface. The developed approach is then applied to adsorption of a symmetric multiblock copolymer onto a symmetric multiblock two-letter surface. Analysis of the adsorption transition point dependence on polymer and surface block sizes and different sets of polymer-surface interaction parameters reveals interesting “odd-even” and “recognition” effects. Beyond the transition point, temperature dependences of the main conformational and thermodynamic characteristics demonstrate that adsorption can occur as a two-stage process, where binding of the polymer chain to the surface is followed by “tuning” the chain conformations in order to maximize the number of energetically favourable contacts. The two-stage adsorption is characterized by appearance of the second maximum on the heat capacity curves. Acknowledgement. This work is supported by the Government of Russian Federation (grant 074-U01). [1] A.A. Polotsky, J. Phys A: Math. Theor., 2012, 45, 425004.
P-191 SELF-ASSEMBLY OF STAR-SHAPED FULLERENE-CONTAINING OLIGOMER OXIRANES WITH HYDROPHOBIC FRAGMENTS IN
DEUTERATED BENZENE AND WATER
E.Yu. Melenevskaya1, V.V. Shamanin1, L.V. Vinogradova1, V.T. Lebedev2, Yu.V. Kulvelis2, D.N. Orlova2
1 - Institute of Macromolecular Compounds RAS, Saint Petersburg, Russia 2 - B.P. Konstantinov Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, Saint Petersburg,
Russia [email protected]
Self-assembly of star-shaped fullerene(C60)-containing oligomers ethylene oxide with the arms having long end hydrocarbon fragments (R = CnH2n, n=1215) in aromatic solvent (D-benzene) and analogous oligomer derivatives of propylene oxide in heavy water has been studied by small-angle scattering. As it was found, in D-benzene the star-shaped molecules of polyethylene oxides have shown the organization into the structures where a part of the arms in stars takes stretched conformations playing the role of physical links between the chains. In this way in solution a polymer cage is created and filled with coil-like chains of linear polymer. This should be considered as a sequence of star-shaped molecular architecture and the presence of hydrophobic end fragments in the arms. In aqueous solutions at low concentration (с = 1.25 gdl1) the oligomer derivatives of propylene oxide were ordered into rod-like structures being the stretched superchains associated via hydrophobic interactions of hydrocarbon end-fragments of the arms. In such supramolecular formations “free” chains of superfluous propylene oxide (not containing C60) take part in the interactions with hydrophobic junctions between star-shaped particles. In this case the extended structures of micelles were formed via their linking by fullerene-containing molecules. In star-shaped structural elements of these superchains the C60-centers were screened by hydrophilic oligomer fragments of propylene oxide. The increase of concentration of superchains stimulates their statistical flexibility when the aggregation number in such a chain was about 10 and the length of chain ~ 100 nm.
P-192 A NUMERICAL AND EXPERIMENTAL STUDY OF POLYZWITTERION CONFIGURATION IN AQUEOUS SOLUTION
A.A. Lezov1, N.A. Volkov1, G.E. Polushina1, A.A. Lezova1, P.S. Vlasov2, A.V. Lezov1
1 - The Physical Faculty SPbSU, Saint-Petersburg,Russia 2 - SPbSU Faculty of Chemistry, Saint-Petersburg,Russia
Ionic macromolecules have an ability to change conformation as a response to variations in the ionic strength and pH of solution. Polymers containing ionic groups may be divided into two classes: polyelectrolytes and polyzwitterions. Polyelectrolytes contain anionic or cationic groups, while polyzwitterions contain both anionic and cationic groups. Polyzwitterions includes both polyampholytes and polybetaines. Polyampholyte contains charged groups on different monomer units, while polybetaine refers to those polymers with the anionic and cationic groups on the same monomer unit. Polymeric zwitterions are of particular interest because of their unique physicochemical properties that predetermine their wide application as materials for biosensors, for amphoteric buffers for electrophoresis, for models of proteins, etc. The solution behavior of polyzwitterion is governed by the charge balance on the polymer chain. A sufficient excess of either charge can cause the polymer to exhibit typical polyelectrolyte behavior. Polymers with charge balance, on the other hand, usually exhibit “anti-polyelectrolyte” behavior, characterized by a collapsed conformation in deionized water and an expanded conformation in the presence of small electrolytes. Profound studies of the conformational properties of polymeric zwitterions in wide range of pH values and ionic strength remain scarce. A polyzwitterionic system, based on poly(2 (diallyl(methyl)ammonium) acetate) (pDM) and N,N diallyl N,N dimethylammonium chloride (DDMC) was investigated via experimental methods, e.g. dynamic light scattering, viscosimetry, high-speed sedimentation. Anti-polyelectrolyte effect was observed for polybetaine samples. It was connected with conformational transition from ideal to swollen coil with increasing concentration of low molecular weight salt. Change of charges share on the chain for the copolymers of pDM with pDDMC leads to the appearance of polyelectrolyte swelling. We used the standard Monte Carlo method to study conformational properties of an isolated polyzwitterionic chain. A polymer was presented as a necklace of freely joined charged hard spheres in a dielectric continuum. An effect of different linear charge distributions, dielectric constant of the solution and concentration of 1:1 salt addition on the end-to-end distance was studied. Behavior of chain, simulated as a sequence of spheres with alternating charges was similar as of the pDM macromolecule. Authors acknowledge the Saint Petersburg State University program for postdocs (grants 11.50.1589.2013 and 11.50.1609.2013).
P-193 SYNTHESIS AND STUDIES OF PHOTO- AND ELECTROLUMINESCENT PROPERTIES OF LUMINOPHORE-
CONTAINING POLYFLUORENES
G.I. Nosova1, D.A. Lypenko2, D.M. Ilgach1, E.I. Maltsev2, A.V. Dmitriev2, A.V. Yakimansky1 1 - Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
2 - Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia [email protected]
Polyfluorenes are widely applied in optoelectronic devices, in particular, in single-layer white light-emitting diodes. In the present work, a series of copolyfluorenes (CPF), containing red-emitting fragments of 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (T-BT-T) and green-emitting moieties of 2,1,3-benzothiadiazole (BT) and 4-pyrrolidinyl-1,8-naphthalimide (NI) derivatives was synthesized via Suzuki polycondensation method. In these copolymers, blue-emitting polyfluorene main chain plays the role of an energy donor, while 2,7-dibromo-carbazole and 2,7-dibromo-[9,9-bis(4-oxyphenyl)-9H-fluorene] were used as functionalizing compounds. It is established that an efficient energy transfer from the polyfluorene backbone to the indicated luminophores occurs when NI and BT are jointly used. The copolymer compositions, providing nearly white photo- and electroluminescence, are found. The copolymer structure is schematically shown below:
(H2C)6(CH
2)6
C8H17 C8H17
OO
O
NN
(H3C)6
(H2 C)
6
OO
NN
ON
N
97.861 1
NS
N
S S
0.03
N
N
N
OO
0.06
O
NN
ON
NN
SN
0.05
n
(CH2)6
NI
BT
T-BT-T
It was revealed that the brightness of light-emitting devices may be essentially enhanced by coating the emissive copolyfluorene layer with an electron-conducting and hole-blocking layer of poly[9,9-bis(6′-diethoxyphosphorylhexyl)fluorene]. Electroluminescent properties were studied for light-emitting diodes with the ITO/PEDOT/CPF/Ca/Al architecture. The electroluminescence spectrum of the polymer is presented in Fig. 1. The emission color is the most close to white light (CIE x=0.344, y=0.403), the brightness reaching 1100 cd/м2. Fig. 1.
The work is supported by the Scientific Program of the Presidium of the Russian Academy of Sciences “Multifunctional materials for molecular electronics” (coordinator – academician S.M. Aldoshin).
0
0.2
0.4
0.6
0.8
1
350 450 550 650 750
Wavelength, nm
EL
, a.
u.
INDEX Abaev V.T. P-168 Abalov I.V. P-080, P-121, P-155, P-
156, P-158, P-165, P-176 Abramchuk S.S. O-71, PO39 Abramov I.G. P-178 Adamchik D.A. P-146 Adamchuk V.K. O-52 Adelsberger J. O-09 Afanasieva N.V. P-150 Akent’ev A.V. O-37 Akhmadeeva L.I. P-010, P-034, P-040, P-052Aleksandrova E.L. P-170, P-178 Aleksandrova G.P. O-47 Aleshin A.N. P-091 Alexandru M. O-55 Alexeev G.V. O-53 Aliev A.D. O-36 Alinovskaya V.A. P-145, P-146 Almjasheva O.V. P-112 Amirova A.I. O-39, P-001, P-008 Anan’eva E. P-107 Anan’eva T.D. O-06, P-165 Andreeva L.N. P-040, P-060, P-109 Antayeva A.S. P-110 Antipina A.Yu. P-076 Antipina M.N. O-48 Antipov M.Yu. P-115 Arkharova N.A. O-50 Artemov M.V. P-133 Astapenko E.P. P-035 Aulov V.A. P-138 Auzely R. O-25 Avagimova N.V. P-098 Avanaseva N.V. P-108 Avetisov V.A. O-26 Ayoub M. O-02 Aysina K.E. P-069 Bakeev N.F. P-173 Baklagina U.G. O-50, P-066, P-070 Bakulev V. P-067 Balabaev N.K. P-141 Balakina M.Yu. O-04, P-042 Balalaeva I.V. O-06, O-46 Ballauff M. L-01 Barashkova I.I. P-077 Bartylla B. O-03 Baschnagel J. O-05 Baskakov A.A. P-027 Batenkin M.A. P-072 Batistakis C. O-61 Baumler H. O-69 Baygildin V.A. P-189
Bekchanov D.J. P-022 Bekeshev A.Z. P-095 Bele A. O-55 Belnikevich N.G. P-015, P-172 Belomoina N.M. P-063 Belyaeva E.V. P-037, P-039 Berezin I.A. P-011, P-025, P-159 Berezkin A.V. O-76 Berkovich A.K. P-131, P-132 Berlin Al.Al. P-141 Bershtein V.A. O-68, P-167 Bezrodniy V.V. P-068 Bezrukova M.A. P-034, P-035, P-040, P-
060, P-109 Billon L. O-22 Binder K. O-15 Birshtein T.M. O-20, P-029, P-050 Bivigou-Koumba A.M. O-09 Blumen A. P-007 Bobrova N.V. P-172 Bochek A.M. P-018, P-155, P-156, P-
157, P-158 Bogdanova Yu.G. O-66, P-103 Bogomolova A. O-34 Bogomolova O.E. P-059 Bogorad N.N. O-06, O-48, P-030, P-032,
P-037, P-039 Boiko Yu.M. O-19 Bondaruk O.M. P-167 Borisov O. O-31 Borisov O.V. O-16 Borisova M.E. P-129 Borisova O. O-31 Borisyuk S.S. P-139 Borovikova L.N. P-090 Borzdoun N.I. P-151 Bossan F. O-81 Brevnov O.N. O-37 Bronnikov S.V. O-60, P-078, P-120 Brozova L. P-048 Budtova T. O-60 Bugrov A. O-67, P-080 Bugrov A.N. P-066, P-112 Bulycheva E.G. P-063 Burceva E.I. P-097 Burov S.V. P-082 Bushin S.V. P-034, P-035, P-040 Buyanov A. P-164 Buzin M.I. P-004, P-063 Bychkovsky P.M. P-145 Bykova Yu.A. P-072 Cai L.-H. L-11 Campbell R.A. O-29
Castro R.A. P-005 Cazacu M. O-55 Chalykh A.E. O-36, P-057, P-064, P-188 Charbonneau C. O-31 Chassenieux C. O-31 Chebotaeva G.S. P-131 Chen J.-P. P-186 Chen P.Y. P-119 Cheng Ch.-Y. P-045 Chernikova E.V. P-027, P-047, P-057, P-
128, P-148 Chernyakov D.D. P-070 Chiu Y.-T. P-186 Chopabayeva N.N. P-110 Chubarova E.V. P-019 Colombani O. O-31 Creanga I. P-092 Cristea M. P-088 Curk T. O-25 Daniel W. L-11 Darinskii A.A. O-13, O-21 Darinskii À.À. P-026 De Garcia Venturini Ch.
O-11
Demidov V.N. P-102 Demin A.A. P-144 Demina T.S. O-49 Deniau-Lejeune E. O-31 Didenko A.L. P-005, P-013, P-113,
P-150 Dmitriev A.V. P-193 Dmitriev I.Yu. P-166, P-171 Dobrodumov A.V. P-082, P-148 Dobrokhotov O.V. P-178 Dobrovolskaya I.P. P-073, P-081 Dolgushev M. P-007 Dommes O.A. P-023 Douglas W.E. O-06 Dubacheva G.V. O-25 Dudkina M.M. O-39 Dyakonova M.A. O-30, P-053 Dzubiella J. L-01 Efimova A.A. P-104 Egorov S.A. O-15 Egorov V.M. O-18 Egorova L.M. O-68 Eisele N.B. O-17 El-Aassar M.R. P-041 El-Kady M.F. P-041 Elokhin V.A. P-066 Elokhovskii V.Yu. P-013, P-094, P-113, P-179Elyashevich G.K. P-154, P-166, P-171, P-
172, P-184 Emelyanov G.A. P-147 Ezhova N.M. P-135 Fagadar-Cosma E. P-092
Fainleib A.M. O-68 Falkovich S.G. O-13, O-73, O-74, P-142,
P-152, P-187 Farzetdinova R.M. O-43 Feldman V.I. O-71 Fernandez-Berridi M.J. O-70 Fernandez-Martinez M. O-81 Filippov A.P. O-39, P-001, P-008, P-009,
P-037, P-039 Filippov S.K. O-34 Fominykh O.D. O-04, P-042 Frenkel D. O-25 Frey S. O-17 Frisken B.J. O-27 Gadirov R.M. P-025 Gaidalovich A.B. P-145, P-146 Gainutdinov R.V. P-028 Galatanu N. O-81 Garkushina I.S. P-135 Gasilova E.R. O-47, P-049, P-070 Gavrilov A.A. P-185 Gavrilova I.I. P-018, P-023, P-024, P-
062, P-082, P-158 Genzer J. L-02 George G.A. O-56 Georgieva R. O-69 Gerard P. O-22 Gerard T. O-60 Gerasimov V.K. P-188 German S.V. O-48, P-123 Giel V. P-099 Girbasova N.V. P-051 Gladchenko S.V. P-108 Glagolev M.K. O-72 Glova A.D. P-153 Goerlich D. O-17 Gofman I.V. P-013, P-036, P-080, P-
121, P-126, P-140, P-142, P-150, P-155, P-156, P-158, P-164, P-165, P-169, P-170, P-176, P-177, P-179
Goikhman M.Ya. P-048, P-127, P-165, P-169, PO60
Goloudina S.I. P-036 Golub N.V. P-145, P-146 Golub O.V. P-001 Golubev E.K. P-138 Golyshev A.A. P-061 Gorbunov A.A. P-002, P-012 Gorshkova M.Y. O-12 Gostev A.I. P-134, P-139, P-148 Goswami S. O-57 Gotlib Yu.Ya. P-007, P-113 Govorun E.N. O-76 Gradzielski M. O-38 Grandfils C. O-49
Gribkova O.L. P-058, P-103, P-105 Grigoriev I.S. O-46 Grigoryeva O.P. O-68 Grigoyan E.S. O-12 Grillo I. O-09, O-30, P-053 Groshikova A.R. P-135 Gubanova G.N. P-087, P-088 Gubarev A.S. P-010, P-034, P-040, P-
052, P-093 Guliy N.S. P-048, P-165 Gumerov R.A. O-35 Gurtovenko A.A. O-33, O-73, O-74, P-076,
P-140, P-142, P-152 Gusakova K.G. O-68 Gvozdik N.A. P-131 Ha C.S. O-62 Han H. O-79 Hanton L.R. O-57 Happ B. O-23 Hassan H. Sh. P-041 Hoghoj P. O-81 Holdcroft S. O-27 Holm C. O-64 Hruby M. O-34 I’lina M.N. P-063 Ilgach D.M. O-06, O-46, O-48, P-025,
P-030, P-032, P-033, P-037, P-039, P-123, P-159, P-193
Ilyash M.Yu. P-125 Imanbaev R.T. P-060 Ionov A.N. P-016 Irusta L. O-70 Isakova A.A. P-103, P-117 Ivan’kova E.M. P-091, P-094, P-112 Ivanchev S.S. P-138 Ivancheva N.I. P-138 Ivankova E.I. O-19 Ivankova E.M. O-67, P-073 Ivanov I.V. P-031, P-032, P-033 Ivanov V.A. O-40, P-186 Ivanov V.F. P-058, P-103 Ivanova A.N. O-32 Ivanova M.V. P-097, P-117 Ivanova V.T. P-097 Izquierdo M.A. O-46 Jager A. O-11 Jager E. O-11 Jaksch S. P-053 Jeong J. O-79 Johner A. O-05 Jonusauskas G. O-51 Jordan R. L-03 Kabanov A. L-03 Kaberov L.I. P-051 Kalninsh K.K. P-114
Kalyuzhnaya L.M. P-018, P-100, P-121, P-158Kamanina N.V. P-078 Karabanova L.V. P-167 Karesoja M. O-14 Karimov M.M. P-020, P-021 Karpushkin E.A. P-133 Kasatkin I.A. O-67 Kashina A.V. P-031, P-032 Kasyanenko N.A. O-53, P-067, P-102 Kechek’yan A.S. P-163 Kechkyan A.S. P-138 Keller S. O-34 Kenny J.M. L-04, O-67, P-187 Khakimjanov B.Sh. P-116 Khalatur P.G. L-06, O-75, P-185 Khasbiullin R.R. P-064 Khizhnyak S.D. O-63, P-181 Khlebnikov O.N. O-65 Khripunov A.K. O-50, P-035 Khudobin R.V. O-80 Khurchak A.P. P-011 Khvatov A.Yu. P-068 Kim H. O-79 Kim Y. O-79 Kipper A.V. P-090 Kirila T.U. P-008 Kirilenko D.A. O-68 Kiselev A.S. O-80 Kishilov S.M. P-027 Klapshin Yu.P. P-174 Klapshina L.G. O-06, O-46 Klebtsov B.N. O-69 Klein J. L-05 Kleptsova L.G. P-124, P-137 Klimova S.A. P-123 Klushin L.I. O-10 Koeckelberghs G. P-034 Kolbina G.F. P-062 Kolomiets I.P. P-040 Komarov P.V. L-06, O-63, O-75, P-046,
P-185, P-186 Kondrashina N.G. P-097 Konnikov S.G. O-68 Kononova S.V. P-066, P-087, P-088, P-
108, P-126 Kopecka J. P-160 Kopylova T.N. P-025 Korlukov A.A. P-004 Korobeinyk A.V. P-167 Korytkova E.N. P-087, P-088 Koshkin A. P-079 Kosovan P. O-64, P-014, P-044 Kosterova R.I. P-145 Kostina J.V. P-027 Kostina Yu. V. P-117 Kostromin S.V. P-078
Kotelnikova N. P-107 Kotelnikova N.E. P-106 Kotov V.Yu. P-069 Kozyr A. P-132 Krasnopeeva E.L. O-58, P-100 Kremnev R.V. P-126 Kruchinina E.V. P-066 Krutko E.S. O-80 Kubarkov A.V. P-130 Kubecka J. P-014 Kuchanov S.I. O-32 Kuchkina I.O. P-138 Kuchkina N.V. P-010 Kudryavtsev V.V. P-005, P-013, P-028, P-
036, P-170 Kudryavtsev Y.V. O-76 Kuimova M.K. O-46 Kukarkina N.V. O-06, P-030, P-031 Kuldova J. P-044 Kulvelis Yu.V. O-58, P-191 Kurkin T.S. P-138, P-163 Kurlykin M.P. P-017 Kuryndin I.S. P-184 Kutin A.A. O-52, P-089 Kutsenko L.I. P-121 Kuznetsova O.V. P-174 Kwak E. O-79 Kyriakos K. O-30, P-053 Ladilina E.Yu. P-174 Lapteva O.S. P-072 Larin S.V. O-73, O-74, P-140, P-142,
P-151, P-152, P-153, P-177, P-187
Laschewsky A. O-09, O-30 Laurinavichyute V.K. P-069 Lavrent’ev V.K. P-187, P-155, P-156,
P-157, P-158 Lavrov N.A. P-189 Lazutin A.A. O-72 Lebedev D.V. O-19 Lebedev O.V. P-163 Lebedev V.T. O-58, P-191 Lebedeva E.V. P-034, P-040 Lebedeva I.O. P-073 Lebedeva M.F. P-018, P-019, P-155, P-
156, P-158 Lee D.B. O-62 Lee H. O-79 Lee S. O-79 Leermakers F.A.M. L-07 Leko M.V. P-082 Lermontova S.A. O-06, O-46 Leshchinskaya A.P. P-135 Lesnichaya M.V. O-47 Lezin I.P. P-030
Lezov A.A. P-010, P-034, P-040, P-052, P-109, P-192
Lezov A.V. P-192 Lezova A.A. P-192 Li Z. O-01 Limpouchova Z. P-044 Lin C.H. O-30 Litvinova L.S. P-015, P-025, P-030, P-
031, P-032, P-033 Lloyd A.W. P-167 Logunova A.A. P-128, P-139 Lomova M.V. O-48 Loretsyan N.L. P-165, P-169 Lovchikov V.A. P-118 Luchinin V.V. P-036 Lukasheva N.V. O-77, P-140, P-143 Luxenhofer R. L-03 Lypenko D.A. P-193 Lysenko E.A. P-047 Lysiakova L.A. O-53 Lyubartsev A.P. O-44 Lyubova T.S. P-174 Lyulin A.V. O-61, O-73, O-74, P-140,
P-142, P-152, P-187 Lyulin S.V. O-73, O-74, P-140, P-142,
P-151, P-152, P-153, P-177, P-187
Lyulina A.S. O-33 Mackova H. O-34 Mahe R. O-81 Makarov I.À. O-37 Makarova L.I. P-175 Mal’tsev E.I. P-065, P-193 Malyar I.V. O-48 Mamonova I.A. O-69 Manevitch L.I. O-32 Marcasuzaa P. O-22 Marikhin V.A. O-18, O-19 Markelov D.A. P-007 Martakova Yu. P-107 Martemyanova J.A. O-40 Martyanov A.M. P-138 Martynenkov A.A. P-016 Mashtak L.A. P-130 Maslennikova T.P. P-087, P-108 Matejicek P. O-38 Matveeva G.N. O-52, P-111 Matyjaszewski K. L-11 Matyushina N.V. P-126, P-170 Mazo M.A. P-141 Mcadam C.J. O-57 Medvedeva D.A. O-18 Meilikhov E.Z. O-43 Melenevskaya E.Yu. P-019, P-191 Melenevsky A.T. P-144
Meleshko T.K. O-06, O-46, O-48, P-030, P-031, P-032, P-033, P-037, P-039, P-123, P-123
Melnikova N.B. P-072 Meshkov I.B. P-001, P-179 Meyer H. O-05 Miagkova L.A. P-126, P-170, P-179 Miasnikova A. O-30 Michailov I.V. O-21, P-026 Michailova N.A. P-043, P-062 Michels M.A.J. O-61 Migulin D.A. P-001 Mikhailidi A. P-107 Mikhailova M.E. P-040 Mikhalovsky S.V. P-167 Mikusheva N.G. P-040 Mirchuk P.Y. P-145 Mironchik V.O. P-146 Mirzakhidov Kh.A. P-022 Misorin A.K. P-029 Mistonova A.A. P-068 Mognetti B.M. O-25 Moratti S.C. O-57 Moskaluk O.A. P-181 Moskalyuk O.A. O-67, P-091 Mueller-Buschbaum P. O-09, O-30 Mukanov K.N. P-110 Mukhamediev M.G. P-020, P-022, P-116 Musteata V. P-120 Musteata V.E. O-55 Muzafarov A.M. P-001, P-008, PO2, PO98 Myasnikova L.P. O-18, O-19 Myrzakhmetova A.A. P-110 Nam S. O-79 Narimani R. O-27 Naumov V.N. P-149 Navarro Baena I. L-04 Nazarova O.V. P-060, P-067, P-109 Nazarychev V.M. O-73, O-74, P-140, P-142,
P-151, P-152 Nechaev S.K. O-26 Neelov I.M. O-13, P-006, P-068, P-125 Nekrasov A.A. P-058, P-103 Nekrasova T.N. P-060, P-067, P-109, P-159Nesterova E.Yu. P-162 Nikiforova E.S. P-144 Nikiforova G.G. P-004, P-063 Nikolaev A.I. P-084 Nikolaev A.Yu. P-027 Nikolaev D.M. P-102 Nikolaeva M.N. P-016 Nikonorova N.A. P-005 Nikonov S.Yu. P-025 Nikonova E.N. P-025 Nikulova U.V. P-057 Nosik N.N. P-097, P-117
Nosova G.I. P-011, P-025, P-043, P-159, P-178, P-193
Novikov R.A. P-004 Novoselov N.P. P-157 Novoskoltseva O.A. L-13 Nurtazina A.S. P-095 Obolonkova E.S. P-175 Obukhov S. O-05 Ogorodnikova E.S. P-134 Okatova O.V. P-023, P-024, P-093 Okrugin B.M. O-13, P-006, P-125 Oleinik E.F. P-141 Omelchenko O.D. P-058, P-103, P-105 Opris D.M. O-55 Orekhov A.S. P-066 Orekhov N.D. O-54 Orell O. P-080 Orlova D.N. O-58, P-191 Osina Ju.K. P-129 Osolodkov M.I. P-102 Ovchinnikov M.M. O-63 Ozerin A.N. P-138, P-163, P-175 Pakhomov P.M. O-63, P-181 Panarin E.F. P-018, P-023, P-024, P-
060, P-062, P-067, P-082, P-109, P-114, P-121, P-135, P-158
Panine P. O-81 Pankova G. P-079 Panov M.F. P-036 Panova T.V. P-055 Papadakis C.M. O-09, O-30, P-053 Papisov I.M. O-07 Papkov V.S. P-004, P-063, P-077 Parilova E.V. P-148 Park J.J. O-62 Paston S.V. P-084 Pasyuta V.M. P-036 Paturej J. L-11 Paul W. O-40 Pautov V.D. P-060 Pavlov A.M. O-48 Pavlov G.M. O-23, O-28, P-023, P-024,
P-043, P-062, P-093 Pavlova E.N. P-099, P-144 Peponi L. L-04 Perelygina O.M. P-065 Perevyazko I. O-23 Perov N.S. P-175 Persoons A. P-034 Peter J. P-099 Petrova N.V. O-69 Petrova S. O-11 Petrova T.F. P-064 Petrova V.A. P-066, P-070 Philipp M. O-30, P-053
Piculell L. L-10 Pientka Z. P-048, P-098 Pikhurov D.V. P-120 Pisarev O.A. P-090, P-135 Plutalova A.V. P-027, P-047 Podeshvo I.V. P-048, P-127, P-165, P-
169, PO60 Podsevalnikova A.N. P-040 Podshivalov A.V. O-60 Polotskaya G.A. P-048, P-098, P-099,
P-100, P-127 Polotsky A.A. O-10, O-20, P-029, P-190 Polshkov V. P-067 Polushina G.E. P-192 Polyakov A.V. P-149 Polyakova I.V. P-135 Polyanichko K.V. P-082 Ponomarev A.N. O-49 Popescu M.-T. P-053 Popov G.I. P-073, P-081 Popova E. P-176 Popova E.N. P-013, P-126, P-150, P-
155, P-156, P-158, P-170, P-179
Popova E.V. P-085, P-086 Popryadukhin P.V. P-073, P-081 Potemkin I.I. O-35 Pozin S.I. P-065 Prazdnikova T.A. P-003 Prochorov V.V. P-065 Puchinyan D.M. O-69 Pulyalina A.Yu. P-127 Purtseladze V.I. P-147 Pyankova L.A. P-066 Pyatnikova D.A. P-104 Pyshkina O.A. P-096, P-130 Qi S. O-10 Rabinovich A.L. O-44, P-083 Racles C. O-55 Radi B. O-56 Radovanova E.I. O-18, O-19 Rakhimov T.Kh. O-42, P-116 Razina A.B. P-017 Reveguk Z. P-067 Richter R.P. O-17, O-25 Richter T. O-64 Rjumtsev E.I. P-115 Rodin V.M. P-118, P-147 Rodinova V.D. P-134 Rodrigues S. O-81 Rogacheva V.B. L-13 Romanov D.P. P-066 Romanova M.S. P-180, P-182 Romashkova K.A. P-087, P-088, P-108 Roshchupkin N.M. P-130 Rosova E.Yu. P-154
Rubatat L. O-27 Rubinstein M. L-11 Rud O.V. P-050 Rudov A.A. O-35 Rukhlya E.G. P-173 Rusinova E.V. P-056 Rustamov M.K. P-020, P-021 Rustamova N.M. P-021 Ryzhov V.A. O-68 Salazkin S.N. P-004 Santuryan Yu.G. P-121 Saprykina N.N. P-075, P-085, P-086, P-
088, P-098, P-100, P-126, P-154, P-157, P-179, P-184
Sapurina I.Yu. P-075, P-097, P-160 Sardon H. O-70 Sasina A.S. P-033 Save M. O-22 Savelyeva A.A. P-059 Savina E.V. P-147 Schmid F. O-10, O-40 Schubert U.S. O-23 Sel’kin A. P-079 Semchikov Yu. D. P-009, P-049 Semenov V.V. P-174 Semenova T.F. P-036, P-036 Semiletova I.V. O-65 Seo J. O-79 Serebryakov E.B. P-153 Sergeyev V.G. P-059, P-096, P-130, P-
131, P-132, P-133 Sergienko N.V. P-175 Serov I.V. P-157 Severyukhina A.N. O-69 Shabsels B. P-079 Shaginyan Sh.A. O-32 Shamanin V.V. P-019, P-191 Shapoval E.S. P-074 Sharipova A.V. O-04 Sharovatova T.V. P-162 Shavykin Î.V. P-026 Shcherbina A.A. O-36, P-057 Shchipunov Y. O-62 Sheiko S.S. L-11 Sheremeteva N.A. P-008 Shevchenko N. P-079 Shevchenko V.G. P-163 Shevtchuk I.L. P-018, P-155, P-158 Shibayama M. L-12 Shifrina Z.B. P-010 Shilyagina N.Yu. O-46 Shirmanova M.V. O-46 Shishov M.A. P-075, P-097 Shvabskaya I.D. P-124, P-137 Sidorenko K.V. P-174 Simonova M.A. P-009
Sinyova S.I. P-087 Sitnikova I.S. P-182 Sitnikova V.E. P-181 Sivtsov E.V. P-128, P-134, P-139, P-
148, P-149 Sklizkova V.P. P-028, P-036 Skorbunova O.V. P-060 Skorik N.A. P-117 Skorik Y.A. P-061, P-070 Skvortsov A.M. O-10, O-78 Smirnov M.A. P-166, P-171 Smirnov N.N. P-178 Smirnova V. P-113, P-176 Smirnova V.E. P-013, P-112, P-179 Smuda K. O-69 Smyslov R.Yu. O-52, P-011, P-025, P-159,
P-169 Sokolov P.A. P-102 Sokolova M.P. O-52, P-089 Soliman T.S.A. P-056 Solomevich S.O. P-145 Solovskaya N.A. P-043, P-178 Solovskij M.V. P-003 Sommer J.U. O-15 Sorochinskaya O.V. P-124, P-137 Spitsyn B.V. P-117 Starcev V.A. P-075 Starostenko O.N. O-68 Stavinsky E.N. P-180 Stavrouli N. P-053 Stegaylov V.V. O-54 Steitz A. L-01 Stejskal J. P-160 Stepanek P. O-11, O-31, O-34 Stepina N.D. P-028 Stetciura I.Y. O-49 Strelnikov I.A. P-141 Subbotina L.I. P-136, P-150 Sudareva N.N. P-085, P-086 Sukhanova T.E. O-52, P-087, P-088, P-089,
P-111, P-136 Sukhorukov G.B. O-48 Sukhov B.G. O-47 Sukhova A.A. P-144 Suvorova E.I. P-109 Suvorova O.M. P-085 Svetlichnyi V.M. P-013, P-028, P-112, P-
126, P-136, P-140, P-142, P-150, P-170, P-179
Svetlychnyi V.M. P-036 Svirskiy K. O-03 Tameev A.R. P-105, P-170 Tarabukina E.B. P-003, P-037, P-092 Tatarinova E.A. P-126, P-179 Telminov E.N. P-025 Tenhu H. O-14
Tenkovtsev A.V. O-39, P-017 Terentyuk G.S. O-69 Tereshatov V.V. O-59 Tihomirov A.K. P-075 Tihomirov V.M. P-149 Timan S.A. O-80 Timerbaeva E.R. P-020 Timpu D. P-088, P-120 Tiscenko G.A. P-154 Titova A.V. P-090 Toikka A.M. P-098, P-127 Tolmachev D.A. O-77, P-143 Tolstikhina A.L. P-028 Toshchevikov V. P-113 Trathnigg B. P-012 Travkin P.G. P-075 Trchova M. P-098 Tsang E.M.W. O-27 Tsitsilianis C. P-053 Tsobkallo E.S. P-091, P-181 Tsvetkov N.V. P-010, P-034, P-040, P-109Tukhbatulina A.I. P-042 Tung S.H. P-119, P-045 Tverskoy V.A. P-058, P-103 Uchman M. O-38 Uhlik F. O-08 Ul’yanov P.G. O-52 Ulyanova N.N. P-023, P-024 Unksov I.N. O-53 Ushkov P.A. P-084 Vaganov G.V. P-094 Vakhrushev A.V. P-002 Valueva S.V. O-52, P-089, P-111 Vannikov A.V. P-058, P-103, P-105, P-117Varga I. O-29 Vasil’ev V.G. P-063, P-077 Vasilevskaya V.V. O-72 Vasserman A.M. P-071 Veniaminov A.V. P-161 Verbiest T. P-034 Veremeychik K.Yu. P-127 Vidyasheva I.V. O-69 Vilegzhanina M.E. O-52, P-089 Vinogradova L.V. O-58, P-030, P-100, P-191 Virnau P. O-40 Vishnevetskaya N. O-30 Vishnevetsky D.V. P-047 Vishnevskiy A.S. P-188 Vlasov P.S. P-192 Vlasov P.V. P-166, P-171 Vlasova E.N. O-18, P-038, P-121, P-157,
P-179 Vokal M.V. O-36 Volchek B.Z. O-18, P-038, P-157 Volgin I.V. P-151, P-152 Volkov A.Ya. O-52, P-087, P-088, P-136
Volkov N.A. P-192 Volkova E.R. O-59, P-183 Volkova I.F. O-12 Volodkin D.V. O-49 Volosova N.S. P-096 Volynskii A.L. P-173 Vuorinen J. P-080, P-094 Vylegzhanina M.E. P-087, P-111, P-136 Wasserman L.A. P-077 Whitby R.L.D. P-167 Wittmer J.P. O-05 Yagovkina M.A. O-68 Yakimansky A.V. O-06, O-46, O-48, O-49, P-
011, P-025, P-030, P-031, P-032, P-033, P-034, P-037, P-039, P-043, P-079, P-123, P-140, P-159, P-165, P-169, P-178, P-193, PO60
Yakushev P.N. O-19, O-68, P-167 Yang A.C.C. O-27 Yarysheva L.M. P-173 Yasnogorodskaya O.G. P-128 Yevlampieva N.P. P-006, P-011, P-115
Yudin V.E. O-67, P-013, P-073, P-080, P-081, P-091, P-094, P-112, P-113, P-126, P-140, P-142, P-150, P-155, P-156, P-158, P-176, P-177, P-179, P-181, P-187
Yukina G.U. P-073, P-081 Yurasov N.A. O-69 Yurkshtovich N.K. P-146 Yurkshtovich T.L. P-145, P-146 Zabivalova N.M. P-155, P-156, P-157 Zaitsev B.A. P-124, P-137 Zaitsev S.D. P-049 Zakharova N.V. P-003, P-037, P-092 Zakharova Yu.A. P-071 Zamyshlyayeva O.G. P-009, P-072 Zdvizhkov A.T. P-004 Zezin A.A. O-71 Zezin A.B. L-13, P-055 Zezina E.A. O-71 Zhang Q. O-53 Zherenkova L.V. P-046, P-185 Zhidkova M.N. P-069 Zhubaev A.K. P-095 Zhulina E.B. O-16 Zhuravlev D.A. P-005 Zhurkin D.V. P-083 Zolotova Yu. I. P-060, P-067, P-109 Zoolshoev Z.F. P-015, P-172 Zorin I.Ì. O-37 Zuev V.V. P-074, P-078, P-120