Short Side‐Chain Perfluorosulfonic Acid Aquivion: From Production to Application

Perfluorinated ionomers are specialty polymers with invaluable thermal and proton transport properties that make them greatly appreciated on the market, mainly for the realization of membranes for fuel cells and water electrolyzers. Among the different materials, the short side-chain perfluorosulfonic acid (PFSA) Aquivion was demonstrated to efficiently work in a broader temperature range compared to its longer side-chain counterparts, enabling high performance and mechanical strength at high temperatures. This appealing property stimulated extensive research on its synthesis from gaseous tetrafluoroethylene and a liquid perfluoro-sulfonyl fluoride vinyl ether, and its applications. Since a recent and comprehensive report on the latest advances in this direction is missing, this review aims to discuss the recent studies in order to elucidate the polymerization mechanism and innovations in reactor technology for Aquivion. Then, the state-of-the-art of its applications, spanning from proton and anion exchange membrane fuel cells (PEMFC and AEMFC) and water electrolyzers (PEMWE) to membranes for gas separation to superacid heterogeneous catalysis, is presented, to highlight the possibilities enabled by this material while taking into account also the major limitations.