Comb‐shaped block poly(arylene ether sulfone ketone)s for anion exchange membranes

A well‐designed architecture is presented here to construct high‐performance anion exchange membranes (AEMs). A series of quaternized fluorene‐containing block poly(arylene ether sulfone ketone)s (QFPESK‐m‐n) is synthesized as the main chains, and grafted with comb‐shaped C8 long alkyl chains for the AEMs. By varying the hydrophilic segment’ length, there has been a significant change in the microstructure as well as phase separation morphology of the membranes, as confirmed by atomic force microscopy. Hence the as‐prepared AEMs with moderate ion exchange capacities (IECs) show enhanced hydroxide conductivities in the range of 28.8―94.7 mS⋅cm−1 from 30 to 80°C. Furthermore, based on the block backbones and hydrophobic comb‐shaped alkyl chains, the AEMs show low‐level swelling ratios of 4.3% to 9.2% at 30°C and from 6.2% to 13.2% at 80°C, and superior ratios of conductivity to swelling. In addition, the QFPESK‐m‐n AEMs also depict acceptable mechanical properties, good thermal stability and an optimizable alkaline stability. A well‐designed architecture which originated from Stiff Bottle‐brush is presented here to construct high‐performance anion exchange membranes.