Azide-assisted self-crosslinking of highly ion conductive anion exchange membranes

作者：He, Shuqing; Liu, Lei; Wang, Xuchao; Zhang, Shufang; Guiver, Michael D.; Li, Nanwen^*

来源：Journal of Membrane Science, 2016, 509: 48-56.

DOI：10.1016/j.memsci.2016.02.045

• Self-crosslinking
• Anion exchange membrane
• Anion conductivity
• Dimensional stability
• Fuel cells

Poly(2,6-dimethyl-phenylene oxide)s (PPO)s with thermally crosslinkable azide groups and "side-chain-type" architecture containing quaternary ammonium and triazole groups were synthesized by Cu-catalyzed "click chemistry". Tough and flexible anion exchange membranes (AEMs) were prepared by solution casting at 70 degrees C. By simple thermal crosslinking at 135 degrees C for 18 h, controllably crosslinked PPO AEMs were obtained. Key properties of the crosslinked AEMs, such as ion exchange capacity, thermal stability, water uptake, hydroxide conductivity and alkaline stability were investigated. The crosslinked membranes maintained high hydroxide conductivities despite their extremely low water uptake (up to 57.5 mS cm(-1) at room temperature, water uptake of 34.5 wt%). The unusually low water uptake and good hydroxide conductivity may be attributed to the crosslinked, "side-chain-type" structures of pendent triazole and cationic groups, which facilitate ion transport. Moreover, the crosslinked membranes exhibited excellent alkaline stability, and retained over 65% of hydroxide conductivity in 5 M or 10 M of NaOH at 80 degrees C for 400 h. It is assumed that crosslinking decreases the water uptake by polymer chain compaction, thus reducing the nucleophilic attack of water or hydroxide at the cationic center. Thus, triazole-containing AEMs with "side-chain-type" architecture appear to be very promising candidates with good stability as high performance anion exchange membrane.

• 出版日期2016-7-1
• 单位中国科学院大学; 中国科学院山西煤炭化学研究所; 内燃机燃烧学国家重点实验室; 天津大学