pol - polymer surfaces and interfaceselectronic structure of a polymer-cathode interface of an...

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POL - Polymer surfaces and interfaces

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I08_POL_452

SOLID CAPILLARITY: WHEN SURFACE PROPERTIES DOMINATE THE MECHANICS

OF SOFT SOLIDS


E. Dufresne *

Department of Materials, ETH Zurich (Switzerland)

The classic models of solid mechanics were developed to describe the behavior of stiff materials. Our recent experiments demonstrate that the deformation of soft solids cannot be described by standard elastic models when the characteristic length-scale of deformation falls below a material-dependent size. In this limit, we see qualitative changes to the interfacial phenomena of adhesion and wetting, as well as dramatic effects on the mechanics of soft composites. We are able to capture the essential features of these phenomena with linear-elastic analytic models that incorporate solid surface tension.

Intriguingly, the apparent surface tension in these phenomena is larger than the expected surface energy. I will describe current experiments targeted at illuminating this discrepancy

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O1-POL _378

CORRELATION OF FOAM FILM STABILITY TO THE INTERFACIAL COMPOSITION

OF POLYELECTROLYTE/SURFACTANT MIXTURES


R. Campbell 1,*, H. Fauser 2, M. Uhlig 2, R. Von Klitzing 2 1Institut Laue-Langevin - Grenoble (France), 2Technical University - Berlin (Germany)

The properties of foams are of interest for many industrial applications such as enhanced oil recovery and in personal care products, and as such they are the focus of many scientific studies [1]. A way to produce stable foam films is to mix surfactants with oppositely charged polyelectrolytes, as the synergistic co-adsorption of the components reduces the free energy of the air/water interface and promotes bubble formation.

We started our work with mixtures of the flexible polyelectrolyte poly(acrylamidomethyl propanesulfonate) sodium salt (PAMPS) and tetradecyltrimethylammonium bromide (C14TAB) showing that there was not a direct correlation between the foam film stability and the surface tension [2]. Then we applied neutron reflectometry (NR) to resolve the interfacial composition at the air/water interface. We showed that a peak in the surface tension can be rationalized in terms of the changing surface composition with bulk composition, rather than bulk precipitation, and the highest foam film stability occurs when there is enhanced synergistic adsorption of both components due to charge screening when the total ionic strength of the system is greatest [3].

It was still unclear, however, the influence of the backbone rigidity of the polyelectrolyte on the resulting foam film properties. Recently we have studied a mixture of the more rigid polyelectrolyte monosulfonated poly(phenylene sulfone) (sPSO2-S220) [4] also with C14TAB. The work revealed stronger synergistic interactions at the interface in sPSO2-S220/C14TAB mixtures than in PAMPS/C14TAB mixtures, which correlates with significantly more stable foam films [5]. Interestingly in this case, highly detailed NR measurements on the high flux FIGARO reflectometer at the Institut Laue-Langevin (Grenoble, France) revealed the presence of a compact interfacial structure and a precise 1:1 interfacial composition, i.e., efficient release of counterions into the bulk, when the foam films were most stable (see figure).

References

[1] R. Petkova et al. Langmuir, 2012, 28, 4996 // [2] N. Kristen et al. J. Phys. Chem. B, 2009 113, 7986 // [3] H. Fauser et al. J. Phys. Chem. B, 2015, 119, 348 // [4] M. Schuster et al. Macromolecules, 2009 42, 312 // [5] M. Uhlig et al. Phys. Chem. Chem. Phys. 2016, under review.

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O2-POL _41

A SPRAYABLE PROTECTIVE COATING FOR MARBLE WITH WATER-BLOCKING

AND ANTI-GRAFFITI PROPERTIES


D. Kronlund 1,*, A. Bergbreiter 1, M. Lindén 2, D. Grosso 3, J.H. Smått 1 1Åbo Akademi University - Åbo (Finland), 2Ulm University - Ulm (Germany), 3Aix-Marseille Université - Marseille (France)

A simple way to apply a pore-lining, protective coating to marble stone products of any size has been developed. The protective, hydrophobic coating is realized by controlling the vesicle behavior of fluorosurfactants via tuning of the solvent polarity, which is achieved by altering the co-solvent composition of the used solutions, and spray-coating 100 ml/m2 of the solutions on marble stones. Using the optimal application conditions, an effective penetration depth of the hydrophobic properties down to at least 0.5 mm was obtained, which was confirmed through combined mechanical grinding and capillary absorption measurements, showing an increase in effective functionalization depth from µm to mm scale when decreasing solvent polarity during application. This ensures a long-term protection against water uptake and long-term stability of the coated stones. Mechanistic studies of the kinetics in the functionalization process show that solution mixtures containing ethylene glycol provide the best functionalization when a penetrating coating is preferred, due to the prolonged functionalization time as a consequence of the slow evaporation rate of ethylene glycol combined with the beneficial shift in the surfactant-vesicle equilibrium towards free surfactants and a preferential shift from large multilamellar vesicles shift into small unilamellar and bilamellar vesicles as well as free surfactants due to the polarity decrease of the solutions as the volatile components in the coated solutions evaporated. The presented coatings also display anti-graffiti properties, allowing for graffiti paint to easily be washed away with a standard pressure washer 3-4 times in a row, after which a new coating can be applied to prolong the lifetime of the surface functionality. The graffiti cleaning results also suggest that water-based solutions could be used when only an anti-graffiti functionality is preferred, as the fast evaporation of the solvent in this system result in a localized higher surfactant concentration on the stone surface, thus providing a more efficiently packed anti-graffiti layer.

Thanks

Coligro oy, The Magnus Ehrnrooth Foundation, the Otto A. Malm foundation, the Swedish Cultural Foundation and the K.H. Renlund Foundation are greatly acknowledged for financial support (D.K.). Furthermore, the Academy of Finland is also acknowledged for funding through the project 259310 (J.H.S.).

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O3-POL _154

IN SITU FTIR STUDY OF CO2 ADSORPTION ON POLYETHYLENE-IMINE

MEMBRANES


S. Moumen 1,*, S. Moumen 2, I. Raible 2, J. Woellenstein 1 1Institute of Microsystems Engineering (IMTEK) - Freiburg (Germany), 2Robert Bosch GmbH, CR/ARY - Stuttgart (Germany)

A miniature CO2 hybrid sensor approach has been developed that combines the CO2 recognition ability of polyethylene-imine (PEI) with NDIR sensing technology. PEI interacts selectively with CO2 via an acid–base reaction giving rise to IR-active bonds whose intensity indicates the amount of CO2 contributing to the adsorption. PEI sorbent layers were coated on porous Alumina membrane using covalent layer-by-layer process with glutaraldehyde crosslinking. The polymer distribution on the surface and in the pores of the membrane was observed using scanning electron microscopy (SEM). The adsorption properties of the sensing layer under different temperatures and gas partial pressures was studied by in situ transmission FTIR spectrometer equipped with a gas cell allowing control over the gas temperature and pressure. The goal is a better understanding of the sorption/desorption process including CO2 diffusion into the bulk and the impact of water vapor on the nature and the amount of the formed species to further optimize the sensing properties of the membrane, mainly regarding kinetics and sorption capacity. For this purpose, the effect of sorption temperature, CO2 gaseous concentration, relative humidity and layer thickness were investigated. In addition, in-situ gravimetrical methods were employed to quantify the amount of CO2 molecules absorbed for different amounts of the polymer.

It was found that CO2 sorption includes two distinct steps: rapid sorption on exposed surface layers of PEI followed by slow diffusion inside the bulk. The diffusion resistance increases with increasing PEI film thickness which slows down the layer capture capacity for the short time scale required for the sensing. The diffusion rate increases when CO2 concentration in the gas phase increases or when the sorption temperature rises to an optimum temperature depending on the layer thickness. The sorption is notably enhanced in the presence of water vapor by changing the adsorption mechanism and the polymer behavior. The diffusion is also found to influence the desorption temperature which varies as a function of the layer thickness.

Hence, to reach the sensing requirements of fast sorption/desorption and large storage capacity, the diffusion effect should be minimized by taking advantage of Al2O3 membrane porosity to increase the specific surface area of the PEI coating.

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O4-POL _369

SILVER NANOPARTICLES USING CHITOSAN AS REDUCING AND STABILIZING

AGENT: A COMBINED XPS, AFM AND UV-VIS STUDY


A. Rego *, A.P. Carapeto *, A.M. Ferraria

CQFM and IN, Instituto Superior Técnico, ULisboa - Lisboa (Portugal)

Silver nanoparticles (NP) can be synthesized using various methods like chemical and/or photochemical reaction1, thermal decomposition2, electrochemical process3, sono-chemical and microwave assisted4 synthesis.

Although these methods can successfully produce silver nanoparticles in an efficient manner they usually involve the use of toxic and hazardous chemicals which have several harmful effects on the environment and human health.

In this work, a system using water as solvent, chitosan as both reducing and stabilizing agent and AgNO3 as silver precursor, is studied focussing on the role of the i) atomic ratio N/Ag; ii) chitosan concentration; iii) the chitosan average molecular weight on the NP 2-D and size distributions as well as on the silver oxidation state. Combination of XPS studies with UV-Vis spectra and AFM images allowed to establish the best ratio N/Ag for each chitosan concentration and molecular weight for obtaining just metallic NP. Figures show UV-Vis spectra for solutions with [chitosan]=7 mg/mL and varying [AgNO3] (in molarity) and the AFM image for a film spread by drop evaporation from the solution with [chitosan]=7 mg/mL and [AgNO3]=3×10-2 M.

Thanks

We acknowledge the financial support from the projects UID/NAN/50024/2013 and for the fellowship SFRH/BPD/108338/2015 (FCT, Portugal). We also aknowledge NATO SFP project 984842 (CATALTEX) for the AFM (Innova, BRUKER) acquisition.

References

[1] Boufi, S., Vilar, M. R., Ferraria, A. M., & do Rego, A. M. B., Colloid Surface A 2013, 439, 151-158.

[2] Hosseinpour-Mashkani, S. M., & Ramezani, M., Mater. Lett. 2014, 130, 259-262.

[3] Khaydarov, R. A., Khaydarov, R. R., Gapurova, O., Estrin, Y., & Scheper, T., J. Nanopart. Res. 2009, 11(5), 1193-1200.

[4] Pal, A., Shah, S., & Devi, S., Mater. Chem. Phys. 2009, 114(2), 530-532.

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P1-POL_15

OPERANDO PHOTOELECTRON SPECTROSCOPY AT POLYMER-CATHODE

INTERFACE OF ORGANIC LIGHT-EMITTING DIODE


Y. Yamashita 1,*, J. Ikeuchi 2, H. Hamamatsu 2, T. Miyamoto 2, S. Tanaka 2, H. Yoshikawa 1 1National Institute for Materials Science - Tsukuba (Japan), 2Sumitomo Chemical Co., Ltd - Tsukuba (Japan)

Recently, organic light-emitting diodes (OLEDs) have been extensively studied for realizing high efficiency, long lifetime, and a good color rendering index. The interface between the light-emitting polymer (LEP) and the electrodes plays an important role in high efficiency OLEDs. Determining the electronic states and potential distribution around the EIL/LEP interface under device operation is indispensable for understanding the electron injection mechanism and improving the device properties.1 Therefore, in the present study, the electronic structure of a polymer-cathode interface of an operating organic light-emitting diode was directly investigated using operand photoelectron spectroscopy. The potential distribution profile of the light-emitting copolymer layer as a function of the depth under the Al/Ba cathode layer in the OLED depended on the bias voltage. We found that band bending occurred in the copolymer of 9,9-dioctylfluorene and N-(4-(2-butyl)-phenyl)diphenylamine (F8-PFB) layer near the cathode at 0V bias, while a linear potential distribution formed in the F8-PFB when a bias voltage was applied to the OLED. Direct observation of the built-in potential and that band bending formed in the F8-PFB layer in the operating OLED suggested that charges moved in the F8-PFB layer before electron injection from the cathode.2

References 1Y. Yamashita et al., J. Appl. Phys. 113, 163707 (2013) 2J. Ikeuchi et al., J. Appl. Phys. 118, 085308 (2015)

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P2-POL_16

THE CHARACTERISTICS OF POLY STYRENE /MONTMORILLONITE

NANOCOMPOSITES


L. Mrah *, M. Benaada

Laboratory of Polymer Chemistry, Department of Chemistry, Faculty of Science, Université D'Oran, BP 1524 31000 El'Menouer Oran Algeria - Oran (Algeria)

A reactive cationic surfactant cetyltrimethylammonium bromide (CTAB) was synthesized for intercalation of montmorillonite Mmt. a Maghnite type of clay. The pristine montmorillonite (Mmt) was obtained from Algerian plant with a cation exchange Organophilic Mmt was prepared by ion exchange between Na+ ions in the clay. CTAB-intercalated Mmt particles were easily dispersed and swollen in styrene monomer, PS/ Mmt-CTAB nanocomposites were synthesized via in situ polymerization, in-situ polymerization, this method is based on the swelling of the silicate layers with the liquid polymer. The polymer composites were characterized using different techniques such as X-ray diffraction (XRD), The results were showed that, the basal space of the silicate layer increased, as determined by XRD, from 12.79 to 32.603 Å.

The transmission electron microscopy TEM Indicate that exfoliation of Mmt was achieved. In our current research,we continue this research and study infrared spectrophotometery (IR), differentialscanning calorimetery (DSC), and balayage electron microscope (MEB) thermal gravimetric analysis (TGA), force atomic microscopy (AFM) and tensile measurements.

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P3-POL_40

MICRODROPLET PULLOUT TEST : INTERFACIAL SHEAR STRENGTH

MEASUREMENTS BETWEEN REACTIVE POLYAMIDE-6 AND CELLULOSIC OR

GLASS FIBRES.


B. Revol 1,*, M. Thomassey 1, F. Ruch 1, M. Bouquey 2, M. Nardin 3 1Pôle Ingénierie des Polymères et Composites, Cetim-Cermat, 21 Rue de Chemnitz - Mulhouse (France), 2Institut Charles Sadron (ICS), UPR 22–CNRS, 23 Rue du Loess - Strasbourg (France), 3Institut de Science des Matériaux de Mulhouse (IS2M), UMR-CNRS 7361, 15 rue Jean Starcky - Mulhouse (France)

Objective

The fibre-matrix interface plays a significant role in the stress transfer from the matrix to the fibres in composite materials. Micromechanical characterization of the interface by microdroplet pull-out test [1] is well adapted to a polyamide-6 matrix. A common method of sample preparation is the melting of the thermoplastic resin on the fibre surface. However, considering the high viscosity polyamide-6 used in our study, this technique implies the degradation of the studied cellulosic fibres.

An innovative way of production of polyamide-6 based composite is reactive injection. Our study explores a new way of sample preparation by wetting the fibres with the reactive mix. Experimental conditions are nearly the same for sample preparation of our micromechanical model and for real size composite injection.

Method and results

The wetting of fibres with the reactive mix leads to good results. The interfacial shear strength will be compared for both types of fibres, using the usual melting method and the wetting with the reactive mix. Glass fibres will be tested in order to compare both methods and will enable us to determine if different adhesion phenomena take place when the sample preparation method changes. Cellulosic fibre will allow us to test the influence of the cellulosic surface on the polymerisation.

Presented results will include optical microscopy for the observation of microdroplets before and after the pull-out test, interfacial shear strength and calculation of contact angle using Carroll’s theory [2].

References

[1] B. Miller, P. Muri, L. Rebenfeld, A Microbond Method for Determination of the Shear Strength of a Fiber/Resin Interface, Compos. Sci. Technol. 28 (1987) 17–32.

[2] B.J. Carroll, The accurate measurement of contact angle, phase contact areas, drop volume, and Laplace excess pressure in drop-on-fiber systems, J. Colloid Interface Sci. 57 (1976) 488–495.

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P4-POL_59

AGEING AND DEGRADATION OF PHENOL-UREA-FORMALDEHYDE BINDER


D. Okhrimenko 1,*, A.B. Thomssen 2, M. Ceccato 1, D.B. Johansson 2, D. Lybye 2, K. Bechgaard 1, S.L.S. Stipp 1 1University of Copenhagen - Copenhagen (Denmark), 2ROCKWOOL International A/S - Hedehusene (Denmark)

Phenol-urea-formaldehyde (PUF) resin is one of the most important thermosetting polymers with irregular structure. It is widely used in many industrial and construction applications as an organic coating and adhesive. For example, in production of mineral wool for insulation, PUF serves as a binder to attach mineral fibers to each other and to create the necessary mechanical integrity and shape of the final product. However, during ageing under high humidity and temperature, hydrolysis degrades PUF surfaces, decreasing product quality. A better understanding of the chemical processes caused by hydrolysis would promote development of more stable PUF binders.

We investigated the composition and stability towards ageing of cured PUF powder binder in hot water (80 °C), using X-ray photoelectron spectroscopy (XPS), element and thermogravimetric (TG) analysis. We analysed the composition of species released from PUF during hydrolysis by electrospray ionization analysis (ESI) of aqueous solutions. Element and TG analysis showed that the extent of PUF curing has an important impact on its stability. XPS also revealed that poorly cured PUF contains a high fraction of methyl ether bonds, -NH-CH2-O-CH2-NH-, which are easily hydrolysed, while longer curing results mostly in more stable methyl bridges, -NH-CH2-NH-. We also observed an indication of urea -NH-CO- bond decomposition and characteristic species in ESI analysis.

Improved understanding of PUF ageing provides clues for making a binder that is more robust, leading to increased quality and stability of mineral wool insulation.

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P5-POL_107

AN ALTERNATIVE STRATEGY TO ACTIVATE POLYMER SAMPLES FOR

ELECTROLESS COPPER DEPOSITION


A. Atli 1,*, S. Simon 1, F.J. Cadete Santos Aires 2, E. Ehret 2, P. Lourdin 1 1Université de Lyon, ECAM Lyon - Lyon (France), 2Université de Lyon, IRCELYON (UMR 5256 CNRS/UCB Lyon 1) - Lyon (France)

The deposition of metals on polymers has a special interest notably in the fabrication of electrically conductive copper tracks for electronics. Electroless deposition is a common industrial method for copper deposition on polymers and includes mainly three steps: surface preparation, surface activation and copper deposition. The first step allows to increase the copper adhesion on the polymer surface. The second step consists in creating the active sites on the polymer surface to initiate the electroless copper deposition. The last step is the copper electroless deposition in a bath. For surface activation, transition metals, and especially palladium, are applied on polymer surfaces by different processes. However these processes are very laborious and, in the case of palladium, highly expensive.

In this work, we demonstrate the feasibility of a simple way of sample preparation for the activation step of polymers for electroless copper deposition. The samples are prepared by incorporation of a small amount (<1 w%) of palladium, nickel or copper acetate into the molten polymer (Liquid Crystal Polymer-LCPVectra®820i) in a blender. Since the blending temperature is kept higher than the decomposition temperature of acetates, during blending, the acetates are thermally decomposed leading to the metallic Pd, Ni or Cu used as active sites for the electroless copper deposition.

The samples are characterized by optical microscopy (OM), Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FTIR), Wide Angle X-ray Diffraction (WAXD) and X-Ray Photoelectron Spectroscopy (XPS). After preparing the sample surfaces, electroless copper deposition is successfully realized. The influence of the nature of acetates on the electroless deposition kinetics is investigated (Fig. 1). The deposited copper layers had a uniform thickness and are free of oxides as characterized by OM and WAXD (Fig. 2). Moreover the possibility to substitute high cost Pd for surface activation by cheaper Ni or Cu is shown.

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P6-POL_113

SEQUENCE CONTROLLED GROWTH OF CROSS-LINKED POLYMER LAYERS ON

SURFACES


S. Steinmüller 1,*, A. Llevot 2, D. Moock 1, B. Ridder 2, F. Scheiba 1, H. Ehrenberg 1, S. Bräse 2, M.A.R. Meier 2, M. Bruns 1 1Karlsruhe Institute for Technology - Institute for Applied Materials - Energy Storage Systems - Eggenstein-Leopoldshafen (Germany), 2Karlsruhe Institute for Technology - Institute of Organic Chemistry - Karlsruhe (Germany)

The functionalization of macroscopic surface areas to generate designed and desired surface properties is a well-known process in many industrial and technical applications. However, one of the remaining challenges is the controlled and uniform coating of structured or three-dimensional surfaces. Especially in the case of electrode surfaces, e.g. in lithium ion batteries, these coating processes are more complicated and not well established. Within the recently installed and DFG funded Cooperate Research Center 1176, Molecular Structuring of Soft Matter, at the Karlsruhe Institute for Technology (KIT), one subproject is dedicated to this special topic.

The controlled creation of different polymer layers with defined physical and chemical properties orthogonally and with defined distance to the surface is investigated in the objective to synthesize an artificial solid electrolyte interface (SEI) for lithium ion batteries. Indeed, in lithium ion batteries, the SEI formed at the interface[1] between the anode (made of graphite) and the electrolyte has a large influence on the electrode stability and therefore battery lifetime.

In this context, the first step of the study is to investigate the electrografting of a diazonium salt on silicon and on highly oriented pyrrolytic graphit (HOPG)[2]. The HOPG hereby is a representative material for the growth of defined artificial SEI interfaces. For an easier characterization, the silicon is used in parallel as a starting point to grow sequence defined polymer layers via thiol-ene and thiol-yne chemistry[3]. Each layer is characterized by ToF-SIMS and XPS surface analyses. The combination of these two instruments, in combination with the use of different marker molecules in each layer, enables the precise characterization and evaluation of the sequence controlled character of our synthetic approach.

Thanks

We would like to thank Thomas Schimmel, Stefan Walheim and Jonathan Berson for preparing samples within their glove box system and Benjamin Bitterer for the synthesis of several precursor molecules for the different polymer layers.

We kindly acknowledge the SFB 1176, funded by the German Research Council (DFG), in the context of projects B2 and Z1 for funding. The K-Alpha+ instrument was financially supported by the Federal Ministry of Economics and Technology on the basis of a decision by the German Bundestag.

References

[1] Kang Xu, Chem. Rev. 2004, 104, 4303

[2] Allongue, P.; Delamar, M.; Desbat, B.; Fagebaume, O.; Hitmi, R.; Pinson, J.; Savéant, J.-M. J. Am. Chem. Soc. 1997, 119, 201

[3] Yun-hui Li, Dong Wang, and Jillian M. Buriak, Langmuir 2010, 26 (2), 1232–1238

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P7-POL_168

CHARACTERIZATION OF SURFACE MODIFIED MATERIALS USED FOR

BIOLOGICAL APPLICATIONS


V. Trouillet 1,*, A. Beloqui 2, K.N.R. Wuest 3, G. Delaittre 2, C. Barner-Kowollik 3, M. Bruns 1 1Institute for Applied Materials (IAM) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT) - Eggenstein-Leopoldshafen (Germany), 2Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT) - Eggenstein-Leopoldshafen (Germany), 3Institute for Chemical Technology and Polymer Chemistry, Preparative Macromolecular Chemistry, Karlsruhe Institute of Technology (KIT) - Karlsruhe (Germany)

The current work presents two different examples of reactions which allow the ligation of polymeric structures onto a diverse set of surfaces used for biological applications: “thiol-click chemistry” and “photoenol chemistry”.

On the one hand we focus on the synthesis and in depth characterization of generated novel nanohybrid material, single-enzyme nanogels (SENs)[1], which possess properties similar to those of their free enzyme counterpart but, more interestingly, they exhibit increased stability against organic solvents and elevated temperatures.

Inherent to any crosslinking polymerization [Fig. A], the presence of remaining reactive double bonds on the SEN surface was exploited for their straightforward immobilization onto thiol-displaying silicon wafers using one class of so-called “thiol-click chemistry”, the thio-Michael addition [Fig. B].

The surface modification steps prior to SEN grafting and the SEN immobilization itself were characterized by X-ray Photoelectron Spectroscopy (XPS). Protein patterning on the surface, and thus the successful “thiol-ene” reaction, was also confirmed by fluorescence microscopy.

On the other hand the present work shows the surface functionalization of nanodiamonds[2] (NDs) with the objective of influencing their properties, such as solubility, stability and biological activity. A light-triggered strategy to attach well-defined functional polymers allows mild reaction conditions like ambient temperature and catalyst-free conditions suitable for biological applications. Photoenol groups were here covalently attached via an amidation reaction to silanized, amine functional NDs. Subsequently, maleimide end group functional poly(styrene) (PS), poly(N-isopropylacrylamide) (PNIPAM) and glycopolymers with lateral mannose units were grafted to the ND surfaces [Fig. C].

The successful photografting was confirmed by X-ray Photoelectron Spectroscopy (XPS) and thermogravimetric analysis (TGA).

References

[1] A. Beloqui, S. Baur, V. Trouillet, A. Welle, J. Madsen, M. Bastmeyer, G. Delaittre, Small 2016, 12, 1716–1722

[2] K. N. R. Wuest, V. Trouillet, A. S. Goldmann, M. H. Stenzel, and C. Barner-Kowollik, Macromolecules 2016, 49, 1712−1721

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P8-POL_188

APPLICATION OF ATMOSPHERIC PRESSURE PLASMA TREATMENT TO IMPORVE

THE ADHESION OF A WATERBORNE PAINT ON POLYMER SURFACES


M. Boudifa 1,*, R. Bole 1, A. Hadjadj 2, J. Marthe 1, A. Tara 2, C. Bruno 1 1Centre Régional d'Innovation et de Transfert de Technologie (CRITT-MDTS), ZHT du Moulin Leblanc - Charleville-Mézières (France), 2Laboratoire d’Ingénierie et Sciences des Matériaux (LISM EA 4695), Université de Reims, Moulin de la Housse, BP 1039, 51687 - Reims (France)

Polypropylene (PP) and Polyvinylchloride (PVC) are widely used plastics with many advantages (cost effective production, low density, corrosion resistant). However, their non-polar character, leads to poor adhesion and hinders a large number of applications such as coatings, adhesives and printing inks. The bonding and finishing problems are mainly related to their low surface energy attributed to the surface chemistry.

In this work PP and PVC polymers were treated by a commercially available atmospheric pressure plasma jet (APPJ) system from Axcys to improve their adhesive strength. Thanks to a six-axis robotic manipulator arm, the effects of the key plasma parameters (distance to the substrate, scanning velocity and pattern of the torch) were first studied by contact angle measurements. The most influential parameters in the plasma treatment were found to be the distance between substrate and nozzle exit and the treatment residence time. For the optimized set of parameters giving the higher surface energy, the surface properties were investigated by XPS and AFM. The modification of the surface chemistry makes the polymer surfaces highly hydrophilic. Such effect mainly depends on the ratio C-O / C=O as reported by other authors [1, 2]. The activated samples exhibit a substantially increased bonding strength for PP and PVC polymers. The improvement may be attributed to an increase of oxygen concentration, and to changes in the topology of the substrate surface due to induced thermal effects.

The results were validated by applying a commercial waterborne paint on plasma treated PP and PVC. The deposited paint was first qualitatively evaluated by the cross-cut test according to the ISO 2049 standard and showed a remarkable enhancement of the adhesion especially on the PP substrates. The adhesion properties of the coating were subsequently evaluated by lap shear tests and confirmed the enhancement of the adhesive strength by a factor of 4.6 on average. Moreover, the critical load was increased along with the scratch-test.

Thanks

Funding of the TRAPASUR project by the ‘Direction de l’Enseignement Superieur, de la Recherche et de l’Innovation’ of the Champagne-Ardenne Region is gratefully acknowledged

References

1. M. Noeske, J. Degenhardt, S. Strudthoff, U. Lommatzsch. Int J Adhes Adhes, 24 (2004), pp. 171–177

2. J. Lai, B. Sunderland, J. Xue, S. Yan, W. Zhao, M. Folkard, B.D. Michael, Y. Wang. Appl. Surf. Sci., 252 (2006), pp. 3375–3379

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P9-POL_283

EFFECTS OF THIN AMORPHOUS HYDROGENATED CARBON (A-C:H) COATINGS

ON SI (100) AND HIGH-DENSITY POLYETHYLENE


C. Fischer *, A. Catena, S. Wehner

Department of Physics, University Koblenz-Landau - Koblenz (Germany)

Silicon wafers (100) as hard material and high-density polyethylene (HDPE) as a soft polymeric material have been covered gradually by thin a-C:H films. Thickness dependent coating series on both materials have been performed by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) with acetylene plasma as carbon source to study the interlayer forming behavior between the base material and the carbon deposition. Two different a-C:H coatings were realized. One has been deposited in an indirect (f-type, more flexible) and the other one in a direct (r-type, more robust) way to the plasma source. Atomic force microscopy (AFM) revealed an unexpected similar morphology for both types and materials. Average height and average area of single evolving grains are analyzed. Besides the grains, a uniformly textured protrusion at the bottom is detectable. Results showed that a smaller amount of carbon deposition for the f-type than for the r-type to obtain similar surface structures independently of the substrate is needed. The average grain area increases for all f- and r-coatings. The average grain height increases in the beginning and reaches a level with nearly constant height. The correlation of average grain heights and average grain areas displays them localized in a limited area, indicating a given regularity throughout the gradually increasing depositions. This comparative study of a-C:H coated substrates provides further insights into the interaction of hard carbon coatings on soft plastic materials.

pol - polymer surfaces and interfaceselectronic structure of a polymer-cathode interface of an...

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