In order to enhance the properties of polymer anion-exchange membranes (ABMs), 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 degrees C for 336 h. The membranes also had high hydroxide conductivity with the values of 34.1-70.5 mS cm(-1) at 80 degrees C. Meanwhile, these membranes possessed good dimensional stability, and their swelling ratio was in the range of 2.5%-7.0% at 80 degrees C. The incorporation of the dense and local imidazole cations in the side chains for AEMs plays an important role for their properties. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.