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Polymers with Tethered Anionic and Cationic Groups as Membranes for Fuel Cells
Author(s) -
Hickner Michael A.,
Tudryn Gregory J.,
Alam Todd M.,
Hibbs Michael R.,
Fujimoto Cy H.
Publication year - 2009
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200950509
Subject(s) - membrane , nafion , cationic polymerization , sulfonic acid , ion exchange , phenylene , polymer chemistry , hydroxide , chemistry , polymer , ammonium , ionic bonding , diffusion , ionic conductivity , ionomer , conductivity , inorganic chemistry , ion , organic chemistry , electrochemistry , copolymer , biochemistry , physics , electrode , electrolyte , thermodynamics
Ionic clustering, water binding, and ion conductivity were studied in polymers functionalized with sulfonic acid and quaternary ammonium hydroxide groups. Small‐angle x‐ray scattering showed that no clustering occurred in the quaternary ammonium containing anion exchange membranes, while evidence of ionic clusters was present in both sulfonated poly(phenylene) and in Nafion, a poly(perfluorosulfonic acid). Interestingly, the water self‐diffusion coefficients of the anion exchange membranes were generally greater than those observed for the sulfonated poly‐ (phenylene)s, and moreover, the water self diffusion coefficients in anion exchange membranes were not a strong function of diffusion time. The water binding behavior lead to increased normalized conductivity in anion exchange membranes as compared to proton exchange membranes at the highest ion exchange capacities.