Facile synthesis of poly(arylene ether ketone)s with pendent oxyhexyltrimethylammonium groups for Robust anion exchange membranes

A quaternized monomer containing two oxyhexyltrimethylammonium groups was synthesized, and successfully polymerized in inexpensive Eaton's reagent. By varying the monomers' ratio (y/x = 2.0, 1.5, 1.0), soluble Q6PEKBP-y/x polyelectrolytes with high molecular weights were synthesized. Anion exchange membranes (AEMs) were facilely prepared via solution casting of Q6PEKBP-y/x. These AEMs exhibited high OH− and HCO3− conductivity (up to 52 mS cm−1 and 26 mS cm−1 at 30 °C, respectively). More prominently, during an accelerated aging test in 1 mol L−1 NaOH at 60 °C for 90 days, Q6PEKBP-2.0 membrane showed no sign of degradation as proved by 1H NMR unambiguously. Meanwhile, GPC tracks during the aging test suggested no degradation of the main-chain. In light of easy synthesis and outstanding membrane properties, AEMs of Q6PEKBP-y/x are promising candidates for applications in alkaline fuel cells and water electrolyzers.