Proton Exchange Membranes (PEM)s Based Upon Increased Hydrophilicity Poly(arylene ether sulfone) Multiblock Copolymers

An increased hydrophilic content hydroquinone based poly(arylene ether sulfone) oligomer (HQS100), was synthesized and coupled with a partially fluorinated poly(arylene ether) hydrophobic segment to form a series of multiblock copolymers. The hydrophobic blocks were varied by using both benzonitrile and ketone based poly(arylene ether) segments in the multiblock copolymers. Both series produced tough, ductile, and transparent membranes when cast from solution, with intrinsic viscosity and stress-strain behavior confirming high molecular weight. Structures were confirmed by using ¹H NMR, and ¹³C NMR was used to ensure ether-ether interchange side reactions were minimized. In addition water uptake, swelling ratio, thermal stability, and conductivity as a function of relative humidity were measured and compared against that of Nafion 212 and the analog biphenol based block copolymer membranes. The synthesis and characterization of these materials will be discussed.