A Single-Step Monomeric Photo-Polymerization and Crosslinking via Thiol-Ene Reaction for Hydroxide Exchange Membrane Fabrication

Abstract

A single step monomeric photo-polymerization and crosslinking via thiol-ene reaction is developed for the preparation of hydroxide exchange membranes (HEMs) in a ternary system with a triallyl triazine, a quaternary ammonium diallyl, and a dithiol. This facile method enables reproducible tuning of the ion exchange capacity and crosslink density. These HEMs demonstrate reasonable hydroxide conductivity, limited alkaline stability, and good thermal stability and have lower water uptakes than other photo-crosslinked HEMs produced with much longer reaction times. Furthermore, this new fabrication method allows the incorporation of catalyst nanoparticles in the hydroxide exchange materials to form thin catalyst layers that are resistant to dissolution in methanol which suggests these polymers can be used in direct alcohol fuel cells (DAFCs).