Proton‐conductive membranes of sulfonated polyphenylsulfone

Polyphenylsulfone was sulfonated by two different methods: reaction with SO₃ and reaction with (CH₃)₃SiSO₃Cl. The products were characterized, and the advantages of both methods are discussed. Much more homogeneous products were obtained from the reaction with (CH₃)₃SiSO₃Cl, along with better control of the sulfonation degree. An alternative method of membrane preparation led to an asymmetric structure, which allowed the combination of high mechanical stability and high proton conductance. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2820–2827, 2002