Phthalimidine based fluorinated sulfonated poly(arylene ether sulfone)s copolymer proton exchange membranes

► Phthalimidine moiety containing new fluorinated poly (arylene ether sulfone)s. ► Superior PEM properties compared to analogs PEM materials. ► Excellent tensile strength, much higher than that of Nafion® 117 membrane. ► Good dimensional stability with low water uptake and swelling ratios. ► Phase separated morphology and proton conductivity up to 50 mS/cm at 80 °C.