Anion exchange membranes with twisted poly(terphenylene) backbone: Effect of the N-cyclic cations

In order to investigate the relationship towards cationic structures and ion exchange membrane performance, three kinds of twisted poly(terphenylene)-based anion membranes (AEMs) with N-cyclic cations were prepared via facile Friedel-Crafts type polycondensation quaternization. The steric hindrance is gradually increased from small piperidinium sterically protected N-spirocyclic quaternary ammonium (QA). poly(terphenylene)s backbone promotes self-assembly polymer chain forms a microphase separated morphology, resulting in highest conductivity 68.7 mS cm−1 (80 °C) for tethered groups (m-TPNPiQA). relative (conductivity/swelling ratio) m-TPNPiQA even higher than that commercial Fumapem FAA-3-50 membrane. Increasing size QA helpful constrain water absorption related swelling but has negative effect on chemical stability. β-Hofmann elimination degradation observed all AEMs during stability test by 1H NMR analysis. demonstrates less 6% ionic capacity loss after 240 h 5 M NaOH solution at 80 °C. results demonstrated performance associated well features groups. A high AEM can be achieved grafting appropriate onto aryl ether-free backbone.