Gel Solutions (Blend/Sonicator)

Tempo-Oxidized Cellulose Membranes: The Tuning of a New MaterialJohn Moore1, Kevin Roberts1, Peter Crooks2, Jamie Hestekin1

1University of Arkansas, Department of Chemical Engineering2University of Arkansas for Medical Sciences, College of Pharmacy

Conclusions Varying the percentage of water-soluble to water-

insoluble ToC fractions changes the properties ofthe film cast.

Insoluble ToC material is not passing through themembrane during the casting process.

Dense ToC membranes are easily produced a usingnon-traditional technique. ToC thin films exhibit atunable hydrophilicity with the possibility ofexhibiting a tunable Tensile strength.

Developing a procedure for the drying of solvents to produce free standing ToC films within a petri dish.

Test biocompatibility of ToC films using a culture growth analysis.

Analyze the transfer of soluble ToC material through the casting process.

Finish investigating the tensile strength of the various fractionalized materials.

Develop a testing apparatus to measure gas barrier properties of the various fractions.

Investigate solubility in various compounds of the water soluble and in-soluble ToC fractions.

Develop a phase inversion technique using the water soluble ToC fraction.

Explore hollow fiber membrane casting techniques with ToC.

Motivation

Fig. 5. ATR-FTIR spectra of cellulosic materialsThis figure shows the oxidized functional group of the tempocellulose material in relation to standard microcrystalline cellulose.As well as, showing that the solvent after filtration is notcontaminated by the casting process and has no residual cellulosicmaterial present.

Motivation

Approach

Conclusions

Ongoing Research

Acknowledgements

Results

Cellulose

Low Tensile Strength, Opaque,

Filtration Applications

ChallengeCellulose is difficult to cast into useful membranes;

innovative methods are needed to develop novel casting techniques for cellulose and its derivatives.

Previous research hasdemonstrated membranesproduced using tempo oxidizedcellulose (ToC) can exhibitdifferent properties based onthe carboxylate content of thepolymer. Furthermore,cellulose has been found toproduce two fractions whenoxidized, a water soluble and awater insoluble fraction. It islikewise hypothesized thatcasting ToC membranes whilevarying the two fractions willallow for the tunability of ToCFilms. Vacuum filtration iscurrently being used as the ToCmembrane production system.

ToC 0.15%

Sonication

Filtration

Fig. 2. Effect of BlendingUsing UV-vis the effect of blending and sonication for thedifferent fractions of Tempo-Oxidized cellulose wereinvestigated.

Fig. 3. Mechanical testing of free standing Tempo-Oxidized Cellulose filmsMechanical testing was performed using an Instron 5944 and anextension rate of 10% strain per minute .

100x

Research reported in this poster was supported by theNational Science Foundation [grant number 1457888] aswell as the Arkansas Chemical Engineering Institute.

Ductile,Transparent,

Barrier Properties

Membrane Casting

20 µm

8001000120014001600180020002200

Wavelength (nm)

Cellulose

C=O

ToC Sol ToC In-Sol

Fig. 4. Proposed Tempo Oxidation MechanismModification of the C6 Carboxyl group.Y. Okita, T. Saito and A. Isogai, Biomacromolecules, 2010, 11, 1696–1700

Fig. 1. Schematic of Cellulose StructureIsogai, Akira, Tsuguyuki Saito, and Hayaka Fukuzumi. "TEMPO-oxidized cellulose nanofibers." Nanoscale 3.1 (2011): 71-85.

Figure 7. Tempo-Oxidized Cellulose FilmThis figure shows the cross section and face of the membrane under a scanning electron microscope.

0

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Different soluble/insoluble TC ratios after sonication and blending.

0%sol 100%sol 50%sol

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15 15s 30 30s 45 45s 60 60s Control

Different humps were createdby different amounts of sonication

Top four lines are blendedBottom four lines sonicated

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Top four lines are blendedBottom four lines sonicated

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7001200170022002700320037004200

H2O 0% 10% 20% 30%

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Cont

act A

ngle

Time (s)

Glass 0g 10g 20g 30g 50g 100g

Fig. 6. Contact angle measurements of fractionalizedTempo-oxidized cellulosic materialsThis figure shows fractionalized Tempo-Oxidized cellulose and theirvarying hydrophilicities.

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ton'

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% Water Soluble Tempo Cellulose

Maximum Load

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aPas

cals

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Tensile stress at Maximum Load

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% Water Soluble Tempo Cellulose

Tensile strain (Extension) at Maximum Load

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% Water Soluble Tempo Cellulose

Modulus (Young's Tensile Stress)

Alpha = 0.01 Maximum Load Tensile stress at Maximum Load Tensile strain (Extension) at Maximum Load Modulus (Young's Tensile stress)P-value 0.000197448 0.00051855 0.042430763 0.001335844

Membrane

Cellulose Modification

Tempo-oxidized Cellulose