Poly(arylene ether)s containing superacid groups (FSPEs) were synthesized as proton conducting membranes for fuel cell applications. To obtain the title ionomers, a series of brominated poly(arylene ether)s were synthesized and perfluorosulfonated via Ullmann coupling. The chemical structure and the ion exchange capacity (IEC) of the FSPEs were characterized by 1H and 19FNMR spectra. Tough, flexible, and transparent membranes with the IEC ranging from 0.34 to 1.29 mequivg-1 were obtained by solution casting. The FSPE membranes did not show obvious glass transition behavior up to the decomposition temperature (180 °C). Microscopic analyses revealed homogeneous and well-connected ionic clusters for the high IEC membrane. Compared to conventional sulfonated poly(arylene ether) membranes, the FSPE membranes showed much higher proton conductivity. The highest proton conductivity of 0.07 S cm-1 was achieved at 80 °C and 86% relative humidity (RH) with the IEC = 1.29 mequivg-1 membrane. A fuel cell using the FSPE membrane showed comparable performance to that of a Nafion cell at 78% RH and 80 °C.
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