Polyacylation as a Versatile Route toward High-Performance Ion Exchange Membranes

This review provides a comprehensive analysis of polyacylation strategies for the fabrication of ion exchange membranes (IEMs), with a focus on recent advances in both cation-exchange and anion-exchange membranes. It elucidates how polyacylation facilitates precise structural design of polymers to optimize ion transport properties, leveraging four key advantages: catalyst diversity (including Lewis acids, trifluoromethanesulfonic acid, and eco-friendly systems such as methanesulfonic acid/P2O5 mixtures); direct functionalization through presulfonated or quaternized monomers for quantitative and spatial control of ion-exchange groups; reaction compatibility allowing concurrent or sequential integration with heterocyclization and hydroxyalkylation; and bottom-up programmability enabled by structurally diverse monomers for architectural membrane tailoring. The discussion delves into critical synthesis strategies─such as the use of functionalized monomers, flexible spacers, and macrocyclic structures─and their effects on key membrane properties including proton conductivity, alkali resistance, and mechanical strength. Furthermore, the review evaluates performance optimization in applications such as fuel cells and electrodialysis, emphasizing improvements in ion-exchange capacity, selectivity, and stability under harsh conditions. These insights establish polyacylation as a versatile and powerful bottom-up synthesis platform for developing next-generation IEMs.