Reactive microporous copolymers with excellent film-forming ability for ion exchange membranes

Abstract Ion exchange membranes (IEMs) are widely used in various fields including ion-selective separation processes and fuel cells. However, synthetic IEMs with a high ion conductivity usually suffer a high swelling ratio in working surroundings. Herein we demonstrate a versatile strategy to develop novel microporous copolymers for the high-performance IEMs via combining merits of polymers of intrinsic microporosity (PIMs) and common functional polymers. As a sample, a series of PIM-1/PES copolymers are synthesized accordingly. These copolymers, other than many PIMs, exhibit a good solubility in common organic solvents including N-methyl-2-pyrrolidone (NMP), and are successfully applied to prepare the high-performance IEMs by chloromethylation and multi-cation crosslinking. The introduction of PIM-1 segments exhibits distinct advantages in the effective water management, swelling control and construction of well-developed ion channels. The resulting PIM-1/PES0.50 anion exchange membrane (AEM), with an ion exchange capacity (IEC) of 1.075 mmol g−1, has a low swelling ratio of 11.0% and a high hydroxide conductivity of 87.6 mS cm−1 at 80 °C. The developed strategy has wide applications in the development of new IEMs materials.