Anion exchange membrane based on poly(arylene ether ketone) containing long alkyl densely quaternized carbazole derivative pendant

A series of poly(arylene ether ketone) copolymers (PAEK-HQACz-x) containing long alkyl densely quaternized carbazole derivative pendant was designed and synthesized for anion exchange membrane. It was found that constructing long alkyl chain between hydrophobic polymer backbone and hydrophilic densely functionalized hydrophilic pendant effective promoted the formation of well-defined microscopic phase separation morphology, in turn enabling high hydroxide conduction and confined dimensional variation. The PAEK-HQACz-0.7 membrane exhibited the hydroxide conductivity of 98.1 mS cm−1 at 80 °C, while the swelling ratio was only 13.5%. The toughness and alkaline stability of PAEK-HQACz-x membranes were also significantly improved by attaching the long alkyl chain onto the quaternized carbazole derivative pendant. The PAEK-HQACz-0.7 membrane was selected for membrane electrode assembly and showed acceptable results. These properties demonstrated such membranes to be promising anion exchange membrane candidates.