Interpenetrating ionomer–polymer networks obtained by the in situ polymerization in pores of PVdF sponges as potential membranes in PEMFC applications

This article presents studies on novel composite electrolytes having the structure of semi-interpenetrating polymer networks for possible application as an electrolyte in fuel cells. The electrolytes were synthesized by soaking the macroporous Kynar-Flex^® (copolymer of vinylidene fluoride and hexafluoropropylene) sponge with water solution of the ionomer followed by the in situ free-radical polymerization of the later. Two ionomers having different acidity-methacrylic acid and p-styrenesulfonic acid were tested. The ionic conductivity of proposed membranes measured for several systems was high enough for applications in fuel cell in the 20–90 °C temperature range. For higher temperatures, the conductivity decreased because of the membrane drying. The fraction of water in the electrolytes was determined using weight loss analysis. The influence of inorganic filler addition and cross-linking ratio on physicochemical and electrochemical properties of the membranes were also tested.