Effect of free radical-induced degradation on water permeation through PFSA ionomer membranes

The effects of chemical degradation, induced by Fenton's reagent reaction, upon water transport properties of Nafion® NR211 membranes are reported. Exposure to free radicals generated using Fenton's reagent causes morphological and structural changes to the membrane that exert a strong effect on transport properties. Liquid-liquid permeation (LLP), liquid-vapour permeation (LVP) and vapour-vapour permeation (VVP) measurements indicate that water permeability increases for degraded membranes as a result of enhanced water sorption (under both partially and fully hydrated conditions). Similarly, a higher water content is responsible for an increase in proton mobility; despite the observation that IEC and proton conductivity decrease.