Novel phosphoric acid (PA)-poly(ether ketone sulfone) with flexible benzotriazole side chains for high-temperature proton exchange membranes

Poly(ether ketone sulfone)s with functionalized benzotriazole side chains are simply designed and successfully obtained by the copolycondensation of 4,4-difluorodiphenylsulfone, 4,4’-dihydroxydiphenylamine and a benzotriazole-based difluoro compound. The resulting polymers are identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance, and the results are consistent with the proposed polymer structures. Owing to the intermolecular hydrogen bonding, the phosphoric acid (PA)-doped polymer membranes show encouraging mechanical properties. Taking advantage of the flexible movement of the benzotriazole in the side chains, the resulting membranes exhibit promising proton conductivities and fuel cell performance, which makes them a strong potential material for applications in high-temperature proton exchange membrane fuel cells