High‐performance poly(m-terphenyl fluorenyl)s containing long flexible side chains with dual 1,2,3-triazole and disulfonated units for proton exchange membranes

Aromatic hydrocarbon proton exchange membranes (PEMs) hold promises as alternatives to Nafion membranes. Here we report on the design and preparation of graft-type PEMs based on poly ( m -terphenyl fluorenyl)s (TSPHFTP-x) with a featured structure of rigid all-carbon aromatic backbones and long flexible side chains with dual 1,2,3-triazole and disulfonated units. Benefiting from the well-designed structure, the TSPHFTP-x membranes exhibit a well-defined bicontinuous microphase separation structure, thus achieving high proton conductivities up to 175.6 mS cm −1 (25 °C) and 303.0 mS cm −1 (80 °C) under 100 % relative humidity, and excellent dimensional stability with swelling ratio below 24 %. Meanwhile, these membranes show good oxidative stability and mechanical properties. In addition, the H 2 –O 2 fuel cell assembled with the TSPHFTP-50 PEM shows a peak power density of 1013 mW cm −2 at 60 °C. This study provides a valuable insight into the design of polymer architectures for high-performance hydrocarbon PEMs.