A STUDY OF CAPILLARY-POROUS STRUCTURE AND SORPTION PROPERTIES OF NAFION PROTON-EXCHANGE MEMBRANES SWOLLEN IN WATER

The standard porosimetry method (SPM) was used to study capillary poro us and sorption properties of Nafion(R) proton-exchange membranes. Por e volume-size and surface-size distributions were recorded together wi th water distributions as a function of capillary pressure and desorpt ion isotherms. The measurements were performed at 20 and 80 degrees C; only a small temperature effect was found for the porous volume struc ture. Using these data, the charge density at the inner pore surfaces was evaluated. The estimate suggested only a small degree of diffusene ss of the proton double layer at the inner pore surface.