Improved property of block copolymer-based anion exchange membranes by attaching multi-ion flexible strings

Abstract

To meet high conductivity and sufficient anti-swelling of anion exchange membranes (AEMs), a collaborative strategy of combining multi-ion flexible string and block backbone is adopted to construct membrane’s architecture. Then a series of adamantane-contained poly(arylether ketone nitrile)s block copolymers has been synthesized and grafted with multi-ion flexible strings to form hydrophilic domains. In addition, the hydrophobic segments with nitrile groups are aimed to enhance the entanglement between chains and limit swelling degrees of membranes. Along the steps, clear phase separation morphologies are formed for creating efficient ionic channels. The resulted AEMs exhibit improved conductivity and dimensional stability at low hydration levels, e.g. conductivity of 91.7–119.4 mS cm⁻¹, swelling ratio (SR) of 14.4%–19.5%, water uptake (WU) of 38.3%–57.9% and λ values of 13.4–15.7 at 80 °C. Furthermore, the AEMs prepared exhibit excellent mechanical properties and good thermal stability below 180 °C. However, further optimization is required for a better alkaline stability.