Sulfonated poly(arylene ether)s with high content of phosphine oxide moieties for proton exchange membranes

► Sulfonated poly(arylene ether)s with high content of phosphine oxide moieties were achieved by direct polycondensation for the first time. ► The high content phosphine-oxide groups of the resulting membranes greatly enhanced the oxidative stability. ► The decafluorobiphenyl units of the resulting membranes effectively decreased the swelling.