Proton exchange membrane materials

Most common membranes for severe conditions are made from perfluori-nated polymers bearing sulfonic acid groups in their side chains, such as Nafion . These membranes are expensive. For this reason, research is focused to develop alternative materials. 

Among a series of other materials, PPS has been tested as proton exchange membrane material, because of its promising properties. Heterogeneous membranes based on medium-sulfonated PPS are made by dispersing the PPS in a poly(olefin) matrix. A commercial fuel cell has been used for membrane testing. It turned out that membranes with high amounts of sulfonated particles are almost as conductive as Nafion 17. However, these membranes exhibit considerably lower diffusive permeabilities to methanol. Further, the membranes are less oxidatively stable. 

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The PEM (proton exchange membrane) material is a perfluorosulfonic acid polymer film. Several manufacturers make PEMs in one form or another. We used one made by du Pont called Nation 117. Nation 117 is a transparent polymer film about 175 microns (0.007 inches) thick. Dow Chemical Co., Asahi Chemical Co., and Chloride Engineers Ltd. make something similar. A patent describing how one PEM manufacturer s film is processed is listed in the references section at the end of this article. 

Y. Gao, G. P. Robertson, M. D. Guiver, X. Jian, S. D. Mikhailenko, K. Wang, and S. Kaliaguine. Sulfonation of poly(phthalazinones) with fuming sulfuric acid mixtures for proton exchange membrane materials. J. Membr. ScL, 227(l-2) 39-50, December 2003. 

Y. Gao, G.P. Robertson, M.D. Guiver, S.D. Mikhailenko, X. Li, S. Kaliaguine, Synthesis of poly(arylene ether ether ketone ketone) copolymers containing pendant sulfonic acid groups bonded to naphthalene as proton exchange membrane materials. Macromolecules 2004, 37(18), 6748-6754. 

Gao Y, Robertson GP, Guiver MD, Jian X, Mikhailenko SD, Wang K, et al. Direct copolymerization of sulfonated poly(phthalazinone arylene ether)s for proton-exchange-membrane materials. J Polym Sci Part A Polym Chem 2003 41 2731 2. 

Mohanty AK, Mistri EA, Ghosh A, Banerjee S. Synthesis and characterization of novel flu-orinated poly(arylene ether sulfone)s containing pendant sulfonic acid groups for proton exchange membrane materials. J Membr Sci 2012 409-410 145-55. 

Y. M. Lee, Synthesis of highly fluorinated poly(arylene ether)s copolymers for proton exchange membrane materials, J. Memb. Sci. 281 (1-2)(2006) 111-120. 

Z. Bai, J.A. Shumaker, M.D. Houtz, P.A. Mirau, T.D. Dang, Ruorinated poly(arylenethioether sulfone) copolymers containing pendant sulfonic acid groups for proton exchange membrane materials. Polymer 50 (6) (2009) 1463-1469. 

A.K. Mohanty, Semifluorinated Sulfonated Poly(Ether Sulfone)s Proton Exchange Membrane Materials (Ph.D. thesis), Indian Institute of Technology, Kharagpur, India, 2013. 

W. Huanga, S.B. Qinga, J.T. Yang, D.Y. Yan, Preparation and characterization of soluble sulfonated polybenzimidazole for proton exchange membrane materials. Chin. J. Polym. Sci. 26 (2) (2008) 121-129. 

Pang J, Zhang H, Li X, Jiang Z (2007) Novel wholly aromatic sulfonated poly(arylene ether) copolymers containing sulfonic acid groups on the pendants for proton exchange membrane materials. Macromolecules 40 9435-9442... 

Mikhailenko, S., and Kaliaguine, S. (2006) Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials. Journal of Polymer Science, Part B Polymer Physics, 44 (16), 2299-2310. 

As mentioned earlier, a variety of membrane materials have been investigated for possible use in hydrogen/alr fuel cells and DMFCs, including sulfonated polyimides, sulfonated poly(arylene ether)s, sulfonated poly(ether ether ketone)s, and phosphoric acid-doped polybenzimidazole [5,321-331]. Many of these membrane materials suffer from poor oxidative stability, excessive swelling when wet and brittleness when dry, and only moderately high proton conductivity. Thus, none of the polymers has yet emerged as the preferred proton exchange membrane material for fuel cell... 

Gao, Y., Robertson, G.P., Guiver, M.D., Jian, X. (2003) Synthesis and characterization of sulfonated poly(phthalazinone ether ketone) for proton exchange membrane materials. Journal of Polymer Science Part A Polymer Chemistry, 41, 497-507. 

Xing, R, Robertson, G.R, Guiver, M.D., Mikhailenko, S.D., Kaliaguine, S., Synthesis and characterization of polyfaryl ether ketone) copolymers containing (hexafluoroisopropylidene)-diphenol moiety as proton exchange membrane materials. Polymer, 2005,46, 3257-3263. 

Li W., Cui Z., Zhou X., Zhang S., Dai L., Xing W., Sulfonated poly(arylene-co-imide)s as water stable proton exchange membrane materials for fuel cells, Journal of Membrane Science, 2008, 315, 172-179. 

P. Mukoma, B.R. Jooste, H.C.M. Vosloo, Synthesis and characterization of cross-linked chitosan membranes for apphcation as alternative proton exchange membrane materials in fuel ceUs, J. Power Sources, 136 (2004) 16-23. 

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