High conductivity and alkali-resistant stability of imidazole side chain crosslinked anion exchange membrane

Poly (aryl ether ketone) polymers (PAEKS) were synthesized by polycondensation of trimethyl hydroquinone , allyl bisphenol S and 4,4-difluorodiphenyl ketone as monomers . A series of uncrosslinked and crosslinked anion exchange membranes (AEMs) with diverse contents of 1-allyl-3-methylimidazolium chloride and 1-vinylimidazole were prepared by grafting and bromination reaction. The 1-vinylimidazole in the AEMs was simultaneously present as a crosslinked agent. 1 HNMR and FT-IR spectra demonstrated the structure of the above PAEKS and AEMs, respectively. TEM images and SAXS profiles showed the formation of distinct hydrophilic/hydrophobic microphase separation in the TCImP membranes, which offered vast of channels for ion transmission. Among them, TCImP-3 membrane showed the highest hydroxide conductivity of 0.144 S/cm at 80 °C. Compared with the uncrosslinked AEMs, the crosslinked AEMs exhibited slightly lower water uptake and swelling ratio. The crosslinked structures in the AEMs were helpful to improve the mechanical property and alkali-resistant stability of AEMs. The hydroxide conductivity of the TCImP-3 membrane kept 0.117 S/cm in 2 M NaOH solutions at 80 °C for 400 h. Meanwhile, crosslinked AEMs showed excellent thermostability. We believe that TCImP membranes are a promising AEMs material.