CO2 CH4 TRANSPORT IN POLYPERFLUOROSULFONATE IONOMERS - EFFECTS OF POLAR-SOLVENTS ON PERMEATION AND SOLUBILITY/

We measured CO2 and CH4 gas permeation through polyperfluorosulfonate ionomer (PFSI) that was solvated with water, methanol, ethanol, or 1-p ropanol. These measurements were compared with predictions based on a two-phase, effective-media, membrane model that considered a number of possible geometries for the distributed phase (the ionic clusters). T he transport parameters (solubility and diffusivity) for each of the p hases and the volume fraction of dispersed phase were either measured independently or estimated from prior literature data. We were unable to match all the experimental observations with this two-phase model. We conclude that different polar solvents can incorporate themselves i nto the flourocarbon 'continuous phase' in ways that will alter the ef fective diffusion coefficient of that phase to gas permeation.