Simultaneous Water Uptake, Diffusivity and Permeability Measurement of Perfluorinated Sulfonic Acid Polymer Electrolyte Membranes

摘要

Water diffusivity in perfluorinated sulfonic acid polymer exchange membranes (PEMs) is tested using two new methods. In the first “static” method the membrane is placed in a water activity gradient in a previously evacuated chamber to eliminate all gas/gas diffusion. In a second “dynamic” method the membrane is placed in an evacuated chamber, and known quantities of water vapor are added to the chamber. Diffusivity and water uptake are calculated by monitoring the change in chamber pressure. Rates of diffusivity were found to be identical regardless of method, or if the membrane was undergoing adsorption or desorption.