Poly(arylene ether) electrolyte membranes bearing aliphatic-chain-linked sulfophenyl pendant groups

► Novel PEEKs bearing aliphatic-chain-linked sulfophenyl pendants were synthesized. ► The cyano-functionalized poly(arylene ether)s exhibited lower water uptake. ► The membranes showed excellent proton conductivities and dimensional stabilities. ► The membranes exhibited distinct nanophase separation morphology.