Highly cross-linked poly(styrene sulfonic acid)-grafted poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) membranes with various thicknesses and their application to direct methanol fuel cell

Abstract

Highly cross-linked poly(styrene sulfonic acid)-grafted poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA-g-PSSA) membranes with various thicknesses have been successfully prepared through the simultaneous irradiation grafting of styrene/divinylbenzene (DVB) onto PFA films with thicknesses of 25, 50, and 100 mm followed by sulfonation to introduce sulfonic acid moiety. It was observed that a concentrated chlorosulfonic acid solution and a high reaction temperature are needed to provide sufficient sulfonic acid as the thickness of the PFA films and the content of DVB both increase. The physicochemical properties of the prepared membranes such as water uptake, proton conductivity, methanol permeability, and chemical stability, were also investigated in this study.