Synthesis and properties of new side-chain-type poly(arylene ether sulfone)s containing tri-imidazole cations as anion-exchange membranes

In order to enhance the properties of polymer anion-exchange membranes (AEMs), a class of side-chain-type poly (arylene ether sulfone)s containing tri-imidazole cations in pendant phenoxyphenyl spacer (i.e., Im-PES-xx) were designed and prepared by polymer grafting reaction. Based on these imidazole functionalized polymers, a series of new AEMs were successfully prepared by their solution coating and ion exchange. The obtained membranes exhibited good alkaline stability with the retention of ion-exchange capacity in the range of 78.5%–83.3% after immersion in 4 M NaOH solution at 80 °C for 336 h. The membranes also had high hydroxide conductivity with the values of 34.1–70.5 mS cm −1  at 80 °C. Meanwhile, these membranes possessed good dimensional stability, and their swelling ratio was in the range of 2.5%–7.0% at 80 °C. The incorporation of the dense and local imidazole cations in the side chains for AEMs plays an important role for their properties.