Preparation and characterization of click-driven N-vinylcarbazole-based anion exchange membranes with improved water uptake for fuel cells

Abstract

A novel side-chain-type anion exchange membrane (AEM) is synthesized using thiol-ene click chemistry and the Menshutkin reaction. The prepared membranes are fully characterized and successfully mitigate the trade-off between conductivity and water uptake. Side-chain-type polymer electrolyte membranes with moderate hydroxide conductivity and improved water uptake are obtained. The thiol-ene click reaction is employed for the synthesis of active monomer 9-(2-((3-(triethoxysilyl)propyl)thio)ethyl)-9H-carbazole (TESPTEC). Using the Menshutkin reaction, TESPTEC is introduced into the brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) backbone. The NVC-50 membrane shows a maximum hydroxide conductivity of 19.84 ± 1.81 mS cm⁻¹ at 20 °C, and 54.69 ± 2.91 mS cm⁻¹ at 60 °C. However, at 20 °C, the water uptake of the membrane NVC-50 is only about 18.36 wt%. After 12 days of alkaline treatment, the NVC-50 membrane shows better alkaline stability than the conventional QPPO membrane.