In this study, poly(aryl ether sulfone) with a 200% degree of chloromethylation was sequentially grafted with 4-hydroxychalcone and p-hydroxybenzyl alcohol (HBA), followed by chlorination (SOCl2) and quaternization with 1,2,4,5-tetramethylimidazole, yielding the target polymer QPSPSF60-TMIm140. 1H NMR confirmed a side-chain composition of 30% chalcone and 70% imidazolium units. Photochemical reactions of QPSPSF60-TMIm140 were carried out under UV irradiation to form cross-linked structures. Two types of anion exchange membranes with different degrees of photocrosslinking (cQPSF60-TMIm140-xmin) were prepared by UV irradiation with different crosslinking times. At 80 °C, the uncrosslinked membrane exhibited a water uptake (WU) of 440.4%, a swelling ratio (SR) of 77.3%, and an ionic conductivity (σ) of 120.5 mS·cm−1 . After 6 min of UV crosslinking, cQPSF60-TMIm140-6min showed reductions in WU and SR of 31.8% and 22.5%, respectively, while σ remained high at 110.1 mS·cm−1 (only an 8.6% decrease). The crosslinked membrane also demonstrated excellent alkaline stability: after 20 days in 1 mol·L‒1 NaOH at 60 °C, it retained 90.4% of its initial ion exchange capacity and 90.0% of its original conductivity. Moreover, photocrosslinking improved the thermal and mechanical properties: the initial decomposition temperature increased by 7 °C and the tensile strength rose by 8.1 MPa compared with the uncrosslinked counterpart. These results indicate that the photo-induced crosslinking strategy effectively enhances dimensional stability and alkaline resistance without significantly compromising ionic conductivity, offering a promising route to high-performance AEMs for fuel cell applications.
ZHANG et al. (Fri,) studied this question.