Terminal Crosslinking of Highly Sulfonated Poly(arylene ether sulfone) Block Copolymers: Synthesis and Properties as Polymer Electrolyte Membranes

Terminally crosslinked, highly sulfonated poly(arylene ether sulfone) ( csPES ) block copolymers with a network structure were prepared by heat‐induced crosslinking of the allyl‐terminated telechelic sulfone polymers using a bisazide. The block copolymers in different hydrophilic and hydrophobic compositions were fully characterized by 1 H NMR . With their highly sulfonated block copolymer structure and terminally crosslinked network, the crosslinked polymer membranes offered excellent proton conductivity under high and low relative humidity, together with hydrolytic, dimensional, and thermal stability.