A novel terminally crosslinked block SPES-b membrane was prepared using an azide-assisted thermal curing of sulfonated multiblock poly(arylene ether sulfone). The membrane morphologies and conductivities were investigated as a function of temperature. The crosslinked block SPES-b membrane showed higher proton conductivities than Nafion (R) both at 20 degrees C (0.09 S/cm) and 100 degrees C (0.77 S/cm). High temperatures induced significant conduction enhancements and morphological changes for SPES-b. (C) 2011 Elsevier B.V. All rights reserved.