We extend the concept of “in situ polymerization in MOF” from Kitigawa and co-workers , to synthesize ion-exchange polymers into MOFs . We report a porous metal−organic framework composite with flexible anion-exchange polymers threaded within the host cavity. Polyvinyl benzyl trimethylammonium hydroxide (PVBTAH) threaded in ZIF-8 (PVBTAH~ZIF-8) is synthesized in steps of chloro-monomer impregnation, in situ polymerization, amination, and alkaline ion exchange. The synthesized non-cross-linked PVBTAH~ZIF-8 material exhibits superior ion-exchange kinetics compared to conventional ion-exchange resins. The open porous structure of MOF allows the physically trapped polymers to contact solvent freely and exchange ions efficiently, as oppose to the conventional ion-exchange resins in which the binding sites are hidden within the polymeric beads, preventing full utilization of ion exchange sites. It has good potential to be applied as a hybrid polymeric electrolyte in advanced fuel cells and flow batteries which demands high ionic selectivity.
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