Synthesis and characterisation of novel poly(arylene ether phosphine oxide)s as proton exchange membranes

A novel series of sulfonated poly(arylene ether phosphine oxide)s containing cheap and easily available sulfonated/non-sulfonated monomer and phosphine oxide monomer were synthesized through direct polycondensation. The structure and thermal properties were characterized. The resulting polymer have high ion-exchange capacity and can be cast into uniform, transparent, and flexible films through solution casting method. The ion exchange capacity, water content, dimensional stability, proton conductivity and oxidative stability of these membranes were thoroughly investigated. Results indicated that polymers with an appropriate degree of sulfonation exhibited excellent performance. For instance, sPFPO-65 has a water uptake of 36.3%, a swelling of 16.4%, and a proton conductivity of 0.085 S/cm at 80 ℃, which is close to that of Nafion 117 membranes. Additionally, it demonstrates superior oxidative stability. Therefore, this membrane has potential applications as a proton exchange membrane material in fuel cells.