Anhydrous proton‐conducting electrolyte based on a nematic poly(methyl acrylate) containing sulfonated side chains

A nematic poly(methyl acrylate) containing terminal sulfonic acids in side chains was prepared by etherification of a brominated mesomorphic precursor with 2‐hydroxyethanesulfonic acid sodium salt. Differential scanning calorimetry measurements and polarized light microscopy observation revealed that the sulfonated polymer exhibited the nematic mesophase at medium temperatures (189–227°C). Electrochemical impedance spectroscopy measurements showed that temperature dependence of anhydrous proton conductivity for the nematic polymer followed the Arrhenius law and that the estimated activation energy was 95 kJ mol −1 in the nematic phase. The proton conductivities of the nematic polymer were two orders of magnitude higher than those of anhydrous Nafion®117 membrane at the same temperature. The enhanced anhydrous proton conductivities of the polymeric electrolyte were ascribed to the orientational order and fluidity of the nematic liquid crystal. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40382.