Tandem Effect of Two Sulfophenylene Groups in Aromatic Polymers for Fuel Cell Membranes

Abstract

While the structural design of sulfonated polyphenylenes for high-temperature operable fuel cell membranes has been mainly focused on the hydrophobic components, there have been few studies on the hydrophilic components. Herein, we designed a hydrophilic monomer (BSP) containing two tandemly linked sulfonated phenylenes (disulfo-biphenylene groups) and copolymerized with fluorinated terphenylene monomer for chemically/mechanically stable, highly proton conductive membranes for fuel cells. Compared with the typical hydrophilic monomer (SP) composed of a single sulfophenylene, the BSP monomer provided the resulting polymer and membrane with higher molecular weight, better mechanical stability, and combined fuel cell durability.