Gas and vapor permeation in a short-side-chain PFSI membrane

The gas and vapor transport into films of Hyflon® Ion H, a short-side-chain perfluorosulfonic acid ionomeric (PFSI) membrane, has been studied at various temperatures (3565°C). The permeability and diffusivity of He, N2 and O2 show an Arrhenius type of dependence on temperature in the range inspected. Pure water vapor permeation was studied at 65°C, at low/medium activity values. The determination of water transport parameters has been performed by solving numerically the water mass balance with a variable diffusion coefficient and accounting for a water immobilization reaction onto hydrophilic sites. The boundary conditions vary in time according to the mass balance on the penetrant volume. The solution allows to represent closely the experimental permeation behavior in all its stages and to calculate local diffusivity values that match well with previous results obtained from water sorption measurements.