Cross-linked poly(arylene ether sulfone)s with side-chain aromatic benzyltrimethyl ammonium for anion-exchange membranes

New poly(arylene ether sulfone) (PAES)-based anion-exchange membranes with side-chain aromatic benzyltrimethyl ammonium are synthesized, and their cross-linked membranes are prepared using tetramethyl alkylene diamine as a cross-linking agent. The new side-chain-type PAES-based membrane (Q) has acceptable hydroxide conductivity ( σ ) of 34 mS cm −1 (80 °C) and high chemical stability in hot alkali solution. Compared with Q, the corresponding series of cross-linked membranes exhibit much higher performance, such as higher dimensional stability and chemical stability, better oxidative stability, and lower methanol permeability ( P M ). Among them, N , N , N ′, N ′-tetramethyl-1,6-diaminohexane-based cross-linked membrane (6CQ20) with IEC of 1.29 meq g −1 shows reasonably high σ of 35 mS cm −1 (80 °C) and low P M of 0.20 × 10 −6  cm 2  s −1 , and displays high alkaline stability against alkali treatment at 60 °C for 216 h with small reduction in hydroxide conductivity by only 14%.