Metal-organic framework threaded with aminated polymer for fast anion exchange

Abstract

We introduce a new approach to synthesize an effective anion exchange material by impregnating a metal organic framework (MOF) with monomers, followed by their in situ polymerization and amination. The MOF composite threaded with flexible anion-exchange polymers in the host cavities demonstrates very fast and reversible ion-exchange activity. We illustrate the approach with polyvinyl benzyl trimethyl ammonium hydroxide (PVBTAH) caged in ZIF-8. It is synthesized in steps of chloro-monomer impregnation, in situ polymerization, amination, and alkaline ion-exchange. The synthesized PVBTAH polymer within ZIF-8 is not cross-linked and exhibits superior ion-exchange kinetics compared to a conventional ion-exchange resin, Amberlyst A26. This PVBTAH~ZIF-8 is robust and better thermal stability than Amberlyst A26. There is great potential to create an effective anion exchange membrane from this new ionomer.