Novel sulfonatecl poly(arylene ether sulfone)s with photo-crosslinkable chalcone moiety in the main chain (SPAESs) are synthesized from 4,4'-dihydroxychalcone, 3,3'-disulfonate-4,4'-difluorodiphenylsulfone and 4,4'-difluorodiphenylsulfone. The resulting polymers are characterized by FT-IR, H-1 NMR, UV and TGA techniques. SPAES membranes are photocrosslinkecl without using a photoinitiator in a hydrated state by UV irradiation (365 nm) to preserve the percolated hydrophilic channels in the hydrated membranes. Untreated SPAES membranes demonstrate high proton conductivity up to 211.61 mS cm(-1) at 80 degrees C for SPAES50. Photocrosslinked SPAES50 membrane maintains proton conductivity up to 191.06 mS cm(-1). The photocrosslinking strategy of SPAES membranes in a hydrated state helps reducing the methanol permeability without sacrificing proton conductivity. Methanol permeability of crosslinked SPAES30 membrane was measured to be in the range from 1.23 x 10(-7) cm(2) s(-1) to 6.48 x 10(-8) cm(2) s(-1), which is only 1/36 of that of Nafion (R) 117. Photocrosslinked SPAES membranes also exhibit excellent mechanical and thermal properties, and improved oxidative and hydrolytic stability. (C) 2014 Elsevier B.V. All rights reserved.