Novel sulfonated poly(arylene ether) containing triphenyl moieties as polymer electrolytes for fuel cell application was successfully synthesized. The sulfonic acid function was only attached at the para positions on the pendant phenyl rings due to the novel sulfonated poly(arylene ether) structures designed. The sulfonated polymers are very soluble in common organic solvents, such as dimethyl sulfoxide, N,N-dimethylacetamide, and can be readily cast into tough and smooth films from solutions. The membrane exhibited very high hydrolytic stability (＞7 d) and the polymer is a thermostable polymer with 5% weight loss temperature of about 362.3 ℃. The membrane also shows excellent oxidative stabilities in Fenton’s reagent (2 mg/L FeSO₄ in 3% H₂O₂).

Key words: sulfonation, sulfonated poly(arylene ether), proton exchange membrane, oxidative stability