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5. A New Ionomer Based on Novel PolyPOM Materials

Author

Herring, Andrew M., primary, Horan, James L,, additional, Kuo, Mei-Chen, additional, Dec, Steven F., additional, Frey, Matthew H., additional, Genupur, Anitha, additional, Ren, Lucy, additional, Yandrasits, Mike A., additional, and Hamrock, Stephen J., additional

Published
2019
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8. Designing Alkaline Exchange Membranes from Scratch

Author

Sarode, Himanshu, primary, Vandiver, Melissa A., additional, Maes, Ashley M., additional, Caire, Benjamin, additional, Horan, James L., additional, Yan, Yating, additional, Li, Yifan, additional, Lindberg, Gerrick E., additional, Dama, James F., additional, Knight, Chris, additional, Jorn, Ryan, additional, Lenz, Martin E., additional, Kasper, Robert, additional, Gu, Shuang, additional, Zhang, Bingzi, additional, Seifert, Sönke, additional, Tsai, Tsung-han, additional, Zhang, Wen X., additional, Coughlin, E. Bryan, additional, Knauss, Daniel M., additional, Yan, Yushan, additional, Voth, Gregory A., additional, Witten, Thomas A., additional, Liberatore, Matthew W., additional, and Herring, Andrew M., additional

Published
2019
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9. Novel Approaches to Immobilized Heteropoly Acid Systems for High Temperature, Low Relative Humidity Polymer-Type Membranes - Final Report

Author

Herring, Andrew M, primary, Horan, James L, additional, Aieta, Niccolo V, additional, Sachdeva, Sonny, additional, Kuo, Mei-Chen, additional, Ren, Hui, additional, Lingutla, Anitha, additional, Emery, Michael, additional, Haugen, Gregory M, additional, Yandrasits, Michael A, additional, Sharma, Neeraj, additional, Coggio, William D, additional, Hamrock, Steven J, additional, and Frey, Matthew H, additional

Published
2012
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12. Crosslinked anion exchange membranes with connected cations

Author

Zhang, Wenxu, primary, Liu, Ye, additional, Liu, Xiaohui, additional, Horan, James L., additional, Jin, Ying, additional, Ren, Xiaoming, additional, Ertem, S. Piril, additional, Seifert, Soenke, additional, Liberatore, Matthew W., additional, Herring, Andrew M., additional, and Coughlin, Edward Bryan, additional

Published
2017
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13. A New Ionomer Based on Novel PolyPOM Materials

Author

Lucy Ren, Matthew H. Frey, Mei-Chen Kuo, Steven F. Dec, Anitha Genupur, Andrew M. Herring, Horan James L, Mike A. Yandrasits, and Stephen J. Hamrock

Subjects
chemistry.chemical_compound, Materials science, chemistry, Composite material, Ionomer
Abstract

The heteropoly acids (HPAs) are a class of inorganic oxides that have some of the highest solid state proton conductivities known at room temperature. At elevated temperatures proton diffusion coefficients in these crystalline materials increase, but, not all the protons are mobile resulting in a decrease of the observed proton conductivity. The proton conductivity in these materials is heavily dependant on the hydration state of the HPA. In order to develop new PEMs based on the HPAs for elevated temperature, dry operation, it will be necessary to both immobilize the HPA and ensure that all of the protons are mobile all of the time. If both these objectives can be obtained a new class of PEMs will be developed that could facilitate the use of PEM fuel cells in automotive applications. We have created a new class of PEM by polymerizing HPA monomers with appropriate co-monomers to produce films with unique proton conducting properties.

Published
2008

14. Multi-Component Fe–Ni Hydroxide Nanocatalyst for Oxygen Evolution and Methanol Oxidation Reactions under Alkaline Conditions

Author

Candelaria, Stephanie L., primary, Bedford, Nicholas M., additional, Woehl, Taylor J., additional, Rentz, Nikki S., additional, Showalter, Allison R., additional, Pylypenko, Svitlana, additional, Bunker, Bruce A., additional, Lee, Sungsik, additional, Reinhart, Benjamin, additional, Ren, Yang, additional, Ertem, S. Piril, additional, Coughlin, E. Bryan, additional, Sather, Nicholas A., additional, Horan, James L., additional, Herring, Andrew M., additional, and Greenlee, Lauren F., additional

Published
2016
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17. Crosslinked anion exchange membranes with connected cations.

Author

Zhang, Wenxu, Liu, Ye, Liu, Xiaohui, Horan, James L., Jin, Ying, Ren, Xiaoming, Ertem, S. Piril, Seifert, Soenke, Liberatore, Matthew W., Herring, Andrew M., and Coughlin, Edward Bryan

Subjects
CATIONS, FUEL cells, MONOMERS, ION channels, STORAGE batteries, WATER purification
Abstract

ABSTRACT: The selective transport of ions has crucial importance in biological systems as well as modern‐day energy devices, such as batteries and fuel cells, and water purification membranes. Control over ion movement can be exerted by ligation, ion channel dimensions, solvation, and electrostatic interactions. Polyelectrolyte hydrogels can provide aligned pathways for counter ion transport but lack mechanical integrity, while polyelectrolyte membranes typically suffer from the absence of an ion transport channel network. To develop polymer membranes for improved ion transport, we present the design of a novel material that combines the advantages of aligned pathways found in polyelectrolyte hydrogel and mechanical robustness in conventional membranes. The ionic species were organized via controlled copolymerization of a quaternizable monomer. Additionally, dimensional stability was then incorporated through a cast/crosslinking method to lock in the network of connected cationic groups. This strategy resulted in dramatically enhanced ion transport, as characterized by ionic conductivities (>80 mS/cm for Cl–, and ∼200 mS/cm for OH–). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 618–625 [ABSTRACT FROM AUTHOR]

Published
2018
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19. Synthesis and characterization of Br- and Cl- anion exchange membranesfor use in alkaline polymer electrolyte fuel cells

Author

Tansey, Emily, Herring, Andrew M., Horan, James L., and Vandiver, Melissa A.

Abstract

Proton exchange membrane (PEM) fuel cells utilize pure hydrogen fuel and platinum-based catalysts. Hydrogen has a relatively low energy density, so large-scale fuel storage is required to operate PEMs. Pt-based catalysts further constrict the manufacturability of PEMs due to scarcity of platinum. As a fuel source, methanol has a greater energy density than hydrogen; however, as PEMs require H+ ionic transport, a fuel processor must be included with the fuel cell assembly to convert CH3OH to hydrogen. Alkaline anion-exchange membrane (AAEM) fuel cells operate directly with methanol. Improved oxidation of CH3OH occurs due to the alkaline nature of AAEMs. Furthermore, AAEMs require significantly less Pt-based metal in their catalysts and benefit from the mechanical and chemical stability that accompany a solid-state electrolyte.

Published
2007
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20. Immobilization of heteropolyacids in PEM fuel cell membranes via copolymerization

Author

Jessop, Jeri D., Herring, Andrew M., Horan, James L., and Kuo, Mei-Chen

Subjects
endocrine system, REMRSEC
Abstract

Nafion is the current standard by which PEM fuel cell membranes are measured. It is a PFSA (perfluoro sulfonic acid) polymer that is used to conduct ions such as protons. This material is only useful at low temperature (less than 100 degrees celsius) and high relative humidity due to protons being transported by water which is not practical for a fuel cell. Research is currently being done to create a new membrane that does not contain PFSA, instead membranes are made using heteropolyacids (HPAs). HPAs are useful because they are strong inorganic acids that have a high water of hydration, meaning a humidifier may not be necessary in a fuel cell. Another positive aspect of HPAs is the ability of protons to hop from HPA molecule to HPA molecule. One limitation of HPAs is their solubility in water. This research is focused on immobilizing the HPA by functionalizing it with an easily polymerizable group so that it becomes a monomer that can be used to make copolymers. Two HPA systems are being presented here, HPA-ethylene and HPA-butyl acyrlate. It is possible that these systems will be more effective than PFSA membranes.

Published
2007
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23. Preparation and Characterization of an Alkaline Anion Exchange Membrane from Chlorinated Poly(propylene) Aminated with Branched Poly(ethyleneimine)

Author

COLORADO SCHOOL OF MINES GOLDEN, Maes, Ashley M, Pandey, Tara P, Vandiver, Melissa A, Lundquist, Lauren K, Yang, Yuan, Horan, James L, Krosovsky, Anastasia, Liberatore, Matthew W, Seifert, Sonke, Herring, Andrew M, COLORADO SCHOOL OF MINES GOLDEN, Maes, Ashley M, Pandey, Tara P, Vandiver, Melissa A, Lundquist, Lauren K, Yang, Yuan, Horan, James L, Krosovsky, Anastasia, Liberatore, Matthew W, Seifert, Sonke, and Herring, Andrew M

Abstract

A new randomly crosslinked polymer is investigated for use as an ion-exchange membrane. The polymer was produced through amination of chlorinated poly(propylene) (PP) with poly(ethyleneimine) (PEI) and quaternized with iodoethane. The synthesis of the new polymer is confirmed by FTIR 1H and 13C NMR. The microstructure of the polymer consists of aggregates on the order of 1 micrometer. Environmentally controlled small and wide angle X-ray analysis showed a relatively featureless amorphous morphology over length scales less than 105 nm through a full range of humidity environments. Little physical swelling of the films were observed, but very high internal water uptake was observed with lamba = 50. The highest in-plane ionic conductivity with chloride as the counter ion observed was 0.29 mS cm 1 at 90 deg C and 95% relative humidity. Infrared spectroscopy was used to monitor the relatively rapid rate of counter-ion reaction of hydroxide with ambient CO2 to form a mixture of carbonate and bicarbonate when exposed to air., The original document contains color images. Published in Electrochimica Acta, 2013.

Published
2013

25. Fast Proton Conduction Facilitated by Minimum Water in a Series of Divinylsilyl-11-silicotungstic Acid-co-Butyl Acrylate-co-Hexanediol Diacrylate Polymers

Author

Horan, James L., primary, Lingutla, Anitha, additional, Ren, Hui, additional, Kuo, Mei-Chen, additional, Sachdeva, Sonny, additional, Yang, Yuan, additional, Seifert, Soenke, additional, Greenlee, Lauren F., additional, Yandrasits, Michael A., additional, Hamrock, Steven J., additional, Frey, Matthew H., additional, and Herring, Andrew M., additional

Published
2013
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26. Synthesis and Characterization of Perfluoro Quaternary Ammonium Anion Exchange Membranes

Author

ARGONNE NATIONAL LAB IL, Vandiver, Melissa A, Horan, James L, Yang, Yuan, Tansey, Emily T, Seifert, Soenke, Liberatore, Matthew W, Herring, Andrew M, ARGONNE NATIONAL LAB IL, Vandiver, Melissa A, Horan, James L, Yang, Yuan, Tansey, Emily T, Seifert, Soenke, Liberatore, Matthew W, and Herring, Andrew M

Abstract

In this study, new alkaline exchange membranes were prepared from the perfluorinated 3M ionomer with various quaternary ammonium cations attached with sulfonamide linkage. The degree of functionalization varied depending on the cation species, resulting in different ion exchange capacities (IECs), 0.33 0.72 meq g(expn -1). There was evidence of polymer degradation when the films were exposed to hydroxide, and hence all membrane characterization was performed in the chloride form. Conductivity was dependent on cation species and IEC, E(sub a) = 36 59 kJ mol(expn -1). Diffusion of water through the membrane was relatively high 1.6 x 10(expn -5) cm(expn 2) s(expn -1) and indicated restriction over a range of diffusion times, 6 700 ms. Water uptake (WU) in the membranes was generally low and the hydration level varied based on cation species, k =6 11. Small-angle scattering experiments suggested ionic aggregation, 37 42 A , independent of cation species but slight differences in long-range order with cation species., The original document contains color images. Published in Journal of Polymer Science Part B: Polymer Physics, 2012. Prepared in cooperation with the Departments of Chemical and Biological Engineering and Chemistry and Geochemistry, Colorado School of Mines, Golden. Sponsored in part by DoE.

Published
2012

27. Understanding Anion Transport in an Aminated Trimethyl Polyphenylene with High Anionic Conductivity

Author

ARGONNE NATIONAL LAB IL, Janarthanan, Rajeswari, Horan, James L, Caire, Benjamin R, Ziegler, Zachary C, Yang, Yuan, Zuo, Xiaobing, Liberatore, Matthew W, Hibbs, Michael R, Herring, Andrew M, ARGONNE NATIONAL LAB IL, Janarthanan, Rajeswari, Horan, James L, Caire, Benjamin R, Ziegler, Zachary C, Yang, Yuan, Zuo, Xiaobing, Liberatore, Matthew W, Hibbs, Michael R, and Herring, Andrew M

Abstract

An alkaline exchange membrane (AEM) based on an aminated trimethyl poly(phenylene) is studied in detail. This article reports hydroxide ion conductivity through an in situ method that allows for a more accurate measurement. The ionic conductivities of the membrane in bromide and carbonate forms at 90 deg C and 95% RH are found to be 13 and 17 mS cm(expn -1) respectively. When exchanged with hydroxide, conductivity improved to 86 mS cm(expn -1) under the same experimental conditions. The effect of relative humidity on water uptake and the SAXS patterns of the AEM membranes were investigated. SAXS analysis revealed a rigid aromatic structure of the AEM membrane with no microphase separation. The synthesized AEM is shown to be mechanically stable as seen from the water uptake and SAXS studies. Diffusion NMR studies demonstrated a steady state long-range diffusion constant, D1 of 9.8 x 10(expn -6) cm(expn 2) s(expn -1) after 50 100 ms., The original document contains color images. Published in Journal of Polymer Science Part B: Polymer Physics, 2012. Sponsored in part by DoE. Prepared in collaboration with the Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, NM. Prepared in cooperation with the Departments of Chemical and Biological Engineering and Chemistry and Geochemistry, Colorado School of Mines, Golden.

Published
2012

28. Designing Alkaline Exchange Membranes from Scratch

Author

COLORADO SCHOOL OF MINES GOLDEN DEPT OF CHEMISTRY-GEOCHEMISTRY, Yan, Yushan, Voth, Gregory A, Witten, Thomas A, Liberatore, Matthew W, Herring, Andrew M, Vandiver, Melissa A, Maes, Ashley M, Sarode, Himanshu, Caire, Benjamin, Horan, James L, COLORADO SCHOOL OF MINES GOLDEN DEPT OF CHEMISTRY-GEOCHEMISTRY, Yan, Yushan, Voth, Gregory A, Witten, Thomas A, Liberatore, Matthew W, Herring, Andrew M, Vandiver, Melissa A, Maes, Ashley M, Sarode, Himanshu, Caire, Benjamin, and Horan, James L

Abstract

There is increasing interest in the alkaline exchange membrane (AEM) fuel cells as this device, if realized, could allow the use of inexpensive metal catalysts and the oxidation of a variety of convenient liquid fuels. While there have been some dramatic early achievements, there is still a need for a fundamental study of anion transport, cation stability and the formation of robust thin films in this area. We have undertaken a comprehensive study of AEMs where theory is linked to well-defined model systems, both in solution and in the solid state, which are characterized using very careful environmental control such that the models can be validated and used predictively. We are also fabricating a number of random copolymer AEMs that can be produced readily in large quantities, allowing us to understand film formation coupled with transport and stability. Those based on perfluorinated backbones invite interesting comparisons with the analogous proton exchange membranes., Presented at the Electrochemical Society Meeting (220th) held in Boston, MA on 9-11 October 2011. Published in ECS Transactions, v41 n1 p1761-1774, 2011. The original document contains color images.

Published
2011

29. Progress towards Robust Anion Exchange Membranes for Fuel Cell Applications

Author

Sarode, Himanshu, primary, Vandiver, Melissa, additional, Caire, Benjamin, additional, Liu, Ye, additional, Horan, James L, additional, Yang, Yating, additional, Li, Yifan, additional, Herbst, Daniel, additional, Lindberg, Gerrick E., additional, Tse, Ying-Lung Steve, additional, Seifert, Sönke, additional, Coughlin, E. Bryan, additional, Knauss, Daniel M, additional, Yan, Yushan, additional, Voth, Gregory, additional, Witten, Thomas, additional, Liberatorre, Mathew, additional, and Herring, Andrew M, additional

Published
2013
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33. A Small-Angle X-ray Scattering Study of the Development of Morphology in Films Formed from the 3M Perfluorinated Sulfonic Acid Ionomer

Author

Liu, Yuan, primary, Horan, James L., additional, Schlichting, Gregory J., additional, Caire, Benjamin R., additional, Liberatore, Matthew W., additional, Hamrock, Steven J., additional, Haugen, Gregory M., additional, Yandrasits, Michael A., additional, Seifert, Sönke, additional, and Herring, Andrew M., additional

Published
2012
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40. Cover Picture: Copolymerization of Divinylsilyl-11-silicotungstic Acid with Butyl Acrylate and Hexanediol Diacrylate: Synthesis of a Highly Proton-Conductive Membrane for Fuel-Cell Applications (ChemSusChem 3/2009)

Author

Horan, James L., primary, Genupur, Anitha, additional, Ren, Hui, additional, Sikora, Benjamin J., additional, Kuo, Mei-Chen, additional, Meng, Fanqin, additional, Dec, Steven F., additional, Haugen, Gregory M., additional, Yandrasits, Michael A., additional, Hamrock, Steven J., additional, Frey, Matthew H., additional, and Herring, Andrew M., additional

Published
2009
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41. Copolymerization of Divinylsilyl-11-silicotungstic Acid with Butyl Acrylate and Hexanediol Diacrylate: Synthesis of a Highly Proton-Conductive Membrane for Fuel-Cell Applications

Author

Horan, James L., primary, Genupur, Anitha, additional, Ren, Hui, additional, Sikora, Benjamin J., additional, Kuo, Mei-Chen, additional, Meng, Fanqin, additional, Dec, Steven F., additional, Haugen, Gregory M., additional, Yandrasits, Michael A., additional, Hamrock, Steven J., additional, Frey, Matthew H., additional, and Herring, Andrew M., additional

Published
2009
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43. Structural and transport effects of doping perfluorosulfonic acid polymers with the heteropoly acids, H3PW12O40 or H4SiW12O40

Author

Meng, Fanqin, primary, Aieta, Niccolo V., additional, Dec, Steven F., additional, Horan, James L., additional, Williamson, Don, additional, Frey, Matthew H., additional, Pham, Phat, additional, Turner, John A., additional, Yandrasits, Michael A., additional, Hamrock, Steven J., additional, and Herring, Andrew M., additional

Published
2007
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46. Synthesis and characterization of perfluoro quaternary ammonium anion exchange membranes.

Author

Vandiver, Melissa A., Horan, James L., Yang, Yuan, Tansey, Emily T., Seifert, Söenke, Liberatore, Matthew W., and Herring, Andrew M.

Subjects
*PERFLUORO compounds, *QUATERNARY ammonium compounds, *SULFONAMIDES, *ION exchange resins, *IONOMERS
Abstract

In this study, new alkaline exchange membranes were prepared from the perfluorinated 3M ionomer with various quaternary ammonium cations attached with sulfonamide linkage. The degree of functionalization varied depending on the cation species, resulting in different ion exchange capacities (IECs), 0.33-0.72 meq g−1. There was evidence of polymer degradation when the films were exposed to hydroxide, and hence all membrane characterization was performed in the chloride form. Conductivity was dependent on cation species and IEC, Ea = 36-59 kJ mol−1. Diffusion of water through the membrane was relatively high 1.6 × 10−5 cm2 s−1 and indicated restriction over a range of diffusion times, 6-700 ms. Water uptake (WU) in the membranes was generally low and the hydration level varied based on cation species, λ = 6-11. Small-angle scattering experiments suggested ionic aggregation, 37-42 Å, independent of cation species but slight differences in long-range order with cation species. © 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1761-1769, 2013 [ABSTRACT FROM AUTHOR]

Published
2013
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47. Understanding anion transport in an aminated trimethyl polyphenylene with high anionic conductivity.

Author

Janarthanan, Rajeswari, Horan, James L., Caire, Benjamin R., Ziegler, Zachary C., Yang, Yuan, Zuo, Xiaobing, Liberatore, Matthew W., Hibbs, Michael R., and Herring, Andrew M.

Subjects
*ANIONS, *IONOMERS, *POLYCYCLIC aromatic hydrocarbons, *FUEL cells, *DIFFUSION
Abstract

An alkaline exchange membrane (AEM) based on an aminated trimethyl poly(phenylene) is studied in detail. This article reports hydroxide ion conductivity through an in situ method that allows for a more accurate measurement. The ionic conductivities of the membrane in bromide and carbonate forms at 90 °C and 95% RH are found to be 13 and 17 mS cm−1 respectively. When exchanged with hydroxide, conductivity improved to 86 mS cm−1 under the same experimental conditions. The effect of relative humidity on water uptake and the SAXS patterns of the AEM membranes were investigated. SAXS analysis revealed a rigid aromatic structure of the AEM membrane with no microphase separation. The synthesized AEM is shown to be mechanically stable as seen from the water uptake and SAXS studies. Diffusion NMR studies demonstrated a steady state long-range diffusion constant, D∞ of 9.8 × 10−6 cm2 s−1 after 50-100 ms. © 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1743-1750, 2013 [ABSTRACT FROM AUTHOR]

Published
2013
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48. A Small-Angle X-rayScattering Study of theDevelopment of Morphology in Films Formed from the 3M PerfluorinatedSulfonic Acid Ionomer.

Author

Liu, Yuan, Horan, James L., Schlichting, Gregory J., Caire, Benjamin R., Liberatore, Matthew W., Hamrock, Steven J., Haugen, Gregory M., Yandrasits, Michael A., Seifert, Sönke, and Herring, Andrew M.

Subjects
*X-ray scattering, *THIN films, *SULFONIC acids, *IONOMERS, *TEMPERATURE effect, *SORPTION
Abstract

An extensive SAXS investigation of the 3M perfluorinatedsulfonicacid ionomer was performed to investigate the morphological changesthat occur during and after annealing at temperatures above the Tα. The effect of film thickness in therange studied, 11–45 μm, was found to be negligible.These properties were studied as a function of equivalent weight from700 to 1100 and correlated with the water uptake as measured by dynamicvapor sorption. Isoscattering points were observed in dynamic annealingexperiments of the unboiled annealed films at q=0.023, 0.096 Å–1. On initial water uptake thesefilms also showed isoscattering points at q= 0.024,0.220 Å–1; q= 0.029, 0.223Å–1; and q= 0.030, 0.211Å–1at 50, 80, or 95 °C, respectively,indicating a decrease in the symmetry of the scattering objects inthese size regimes. Isoscattering points were absent in similar wateruptake experiment for the films after boiling. [ABSTRACT FROM AUTHOR]

Published
2012
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49. A Combined Theoretical and Experimental Investigation of the Transport Properties of Water in a Perfluorosulfonic Acid Proton Exchange Membrane Doped with the Heteropoly Acids, H3PW12O40or H4SiW12O40

Author

Liu, Yuan, Sambasivarao, Somisetti V., Horan, James L., Yang, Yuan, Maupin, C. Mark, and Herring, Andrew M.

Abstract

The 3M 825EW perfluorosulfonic acid (PFSA) ionomer was doped with the heteropoly acids (HPAs), H3PW12O40(HPW) and H4SiW12O40(HSiW). Dynamic vapor sorption measurements at 95% RH showed a decrease in water content as a result of HPA doping from λ = 8.05 for the undoped 825EW 3M ionmer to λ = 4.40 for a 5% HSiW doped film. FTIR measurement revealed strong interactions between the HPAs, ionomer, and H2O. Irrespective of hydration level, it was found that the PFSA films showed tortuous proton diffusion behavior. At maximum hydration and 25 °C, the self-diffusion coefficient of water was found to decrease upon addition of HPA from 4.97 to 2.19 (×10–6cm2/s) for the undoped 825EW 3M ionomer and 1% HPW, respectively, in excellent agreement with computation. The model at low HPA loadings revealed the decreased diffusion coefficient was due to the water preferentially residing near the HPA as opposed to the SO3–groups. The addition of HPA generally improved overall conductivity due to additional formation of hydrogen-bonding networks between the HPA particles. At high RH, it was observed that the proton conductivity increased while the water diffusion coefficient decreased as HPA was incorporated. In addition, a mismatch between the conductivity values and those calculated from the Nernst–Einstein equation using the self-diffusion coefficient of water in the system indicated an enhancement in Grotthuss hopping mechanism upon addition of HPA.

Published
2014
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50. Fast Proton Conduction Facilitated by Minimum Water in a Series of Divinylsilyl-11-silicotungstic Acid-co-Butyl Acrylate-co-Hexanediol Diacrylate Polymers

Author

Horan, James L., Lingutla, Anitha, Ren, Hui, Kuo, Mei-Chen, Sachdeva, Sonny, Yang, Yuan, Seifert, Soenke, Greenlee, Lauren F., Yandrasits, Michael A., Hamrock, Steven J., Frey, Matthew H., and Herring, Andrew M.

Abstract

Studies of proton transport in novel materials are important to enable a large array of electrochemical devices. In this study, we show that heteropoly acids (HPAs) when immobilized in polymer matrixes have highly mobile protons. Divinyl-11-silicotungstic acid, an HPA, was copolymerized with butyl acrylate and hexanediol diacrylate at various weight percentage loadings from 25% to 85% using UV initiated polymerizations. The resultant films were tan colored flexible sheets of ca. 120 μm thickness. The morphology of these films varied with loading, showing phase separation into clustered HPA above a 50 wt % loading and lamella morphologies above an 80 wt % loading. Water uptake was strongly associated with the HPA clusters, which facilitated transport of protons. This was realized by proton conductivities as high as 0.4 S cm–1at 95 °C and 95% RH and 0.1 S cm–1at 85 °C and 50% RH. Pulse field gradient spin echo NMR measurements indicated that water self-diffusion was fast (1.4 × 10–5and 4.4 × 10–5cm2s–1for 50% and 100% RH, respectively) at 80 °C. We show that the water in these systems is highly associated with the HPA clusters and that fast proton transport is facilitated by as few as 3 water molecules per proton.

Published
2014
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