Partially crosslinked comb-shaped PPO-based anion exchange membrane grafted with long alkyl chains: Synthesis, characterization and microbial fuel cell performance

Abstract

Anion exchange membranes (AEMs) with higher ion exchange capacities (IECw) are limited to applications due to excessive swelling and higher water uptake. Crosslinked macromolecular structures have been a strategy to balance between ionic conductivity and swelling in membranes. However, highly crosslinked AEMs are usually mechanically brittle and poorer in ion transport. Thus we report a series of partially diamine crosslinked (X = 10%, 15%, 20%) comb-shaped AEMs functionalized with dimethylhexadecylammonium groups exhibiting improved flexibility, water uptake and swelling properties over conventional un-crosslinked or fully crosslinked materials. The higher conductivities in these PPO AEM(X) (for example, X = 20%, IECw = 1.96 mmol/g, σ(OH−) ~ 67 mS/cm at 80 °C) are attributed to the distinct nanophase separation as observed in SAXS and AFM analyses. Finally, the microbial fuel cell performances of the membranes were compared with commercially available cation and anion exchange membranes.