Sulfonated poly (aryl ether sulfone) containing 1, 3, 4-oxadiazole as proton exchange membranes for medium-high temperature fuel cells

Double fluoride 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole (BFO) monomer was synthesized. Copolymerization of BFO, 2,2-bis(4-hydroxypheny)propane (bisphenol A) and 3′3-disulfonate-4′4-dichloro dipheny sulfone (SDCDPS) at different molar ratio resulted in a new poly (aryl ether sulfone) containing 1, 3, 4-oxadiazole polymers (SPAESO). The structures of monomer BFO and copolymer were confirmed by FT-IR and 1H NMR. The TEM pictures showed that the ion clusters were formed and distributed evenly in SPAESO copolymer matrix. The sulfonated polyoxadiazole membranes exhibited excellent thermal, dimensional and oxidative stability and lower methanol diffusion coefficient. The proton conductivity of SPAESO-3 was 7.5 × 10−2 Scm−1 at 120 °C while the methanol permeability coefficient of SPAESO-3 was only 2.23 × 10−7 cm2S−1 at 25 °C. According to the comprehensive performance, the sulfonated polyoxadiazole membranes may be the alternative materials as proton exchange membrane for PEMFC at medium-high temperature operation.