Synthesis and characterization of fluorinated and sulfonated poly(arylene ether-1,3,4-oxadiazole) derivatives and their blend membranes

In this study we present the synthesis and characterization of sulfonated poly(arylene ether-1,3,4-oxadiazole) derivatives. The polymers were prepared by the polycondensation reaction of bisphenol A, bisphenol S and bisphenol AF with 2,5-bis(pentafluorophenyl)-1,3,4-oxadiazole, followed by sulfonation with oleum. The polymers were characterized using elemental analysis, 1H, 13C and 19F NMR analysis. The obtained polyelectrolytes were blended with excess of polybenzimidazoles producing stable and flexible polymer films which showed high thermal stability and reasonable proton conductivity after doping with phosphoric acid. This study confirms that poly(arylene ether 1,3,4-oxadiazole)s are promising candidates as proton exchange membranes in intermediate- and high-temperature fuel cell applications.