Poly(arylene ether ketone) Copolymer Grafted with Amine Groups Containing a Long Alkyl Chain by Chloroacetylation for Improved Alkaline Stability and Conductivity of Anion Exchange Membrane

We report simple and controllable acetylation of poly­(arylene ether ketone) (PK) followed by Menshutkin reaction (quaternization), to prepare a highly alkaline stable and conductive (phase-separated) anion exchange membrane (AEM). A long side alkyl chain grafted with ammonium groups facilitates decent hydrophilic/hydrophobic microphase separation. Prepared AEMs exhibited improved conductivity, alkaline stability, and water resistivity, because of well-designed membrane architecture. Under alkaline conditions, nucleophilic substitution reaction and/or Hofmann elimination reaction (β-hydrogen) are expected to protected by grafting of a large volumetric alkyl chain (C = 16) with amine groups responsible for steric hindrance. Suitably assessed PK-QD-48 AEM reveals 0.81 V open circuit voltage (OCV) corresponding to 25.53 mW cm^–2 power density at 65 °C in alkaline direct methanol fuel cell (ADMFC) operation. The reported synthetic strategy offers a novel route for preparing highly conducting, and alkaline stable, AEMs for fuel cells and diversified electrochemical applications