Synthesis of poly(styrene-b-styrenesulfonic acid) and its blend with PPO for proton exchange membrane.

Poly(styrene-b-styrenesulfonic acid sodium salts) (PS-b-PSSNa) were synthesized via stable free radical polymerization (SFRP) using 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radical and the block copolymers were blended with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) to prepare polymer electrolyte membranes (PEM). The ratio of block length and total molecular weight of PS-b-PSSA were varied, and weight ratio of PPO/PS-b-PSSA was also controlled. The blend membranes showed good proton conductivity, low methanol permeability, and good thermal property.