Crosslinked poly(arylene ether sulfone) block copolymers containing pendant imidazolium groups as both crosslinkage sites and hydroxide conductors for highly selective and stable membranes

Crosslinked poly(arylene ether sulfone)s with pendant imidazolium units, both as crosslinkage sites and hydroxide conductors, were developed as anion exchange membranes (AEMs). These crosslinked membranes, with IECs of 0.80–1.21 meq/g, showed high hydroxide conductivity over 0.01 S/cm at 20 °C and 0.06 S/cm at 80 °C. Furthermore, the crosslinked membranes containing imidazolium groups on the side chains of the polymer exhibited good thermal, mechanical and dimensional stability, as well as excellent chemical stability at high pH. The combination of high hydroxide conductivity and low methanol permeability caused these crosslinked membranes to have very high selectivity up to 13 × 105 S s/cm3, suggesting our crosslinked membranes are suitable for DMAFCs. These membranes can also be used for various other applications including gas separations.