A simple strategy based on a high fluorinated polymer blended with a fluorinated polymer containing phosphonic acid to improve the properties of PEMFC

In order to enhance the thermo-chemical and mechanical proton exchange membrane (PEM) properties, a series of five blend membranes made from poly(vinylidene fluoride-co-chlorotrifluoroethylene) (poly(VDF-co-CTFE)) with a fluorinated copolymer containing phosphonic acid was performed. The mechanical properties of these blend membranes were assessed by dynamic mechanical analysis (DMA). In order to determine the influence of fluorinated copolymer on the blend membrane morphology, a SAXS study was performed. The presence of the fluorine atoms from poly(VDF-co-CTFE) allows us to obtain membranes with a better structuration, but also to enhance the oxidative stability in the presence of radicals. The best result obtained show a proton conductivity of 40mS.cm-1 at 80°C under fully hydrated conditions.