title: Click Chemistry Finds Its Way in Constructing an Ionic Highway in Anion-Exchange Membrane.
abstract: To find the way to construct an ionic highway in anion-exchange membranes (AEMs), a series of side-chain-type alkaline polymer electrolytes (APEs) based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) polymer backbones were synthesized via Cu(I)-catalyzed click chemistry. The resulting triazole groups and quaternary ammonium (QA) groups facilitate the formation of a continuous hydrogen bond network, which will lead to high hydroxide conductivity according to Grotthuss-type mechanism. Microphase separation induced by long alkyl side chains contributes at the same time to further improving the hydroxide conductivity of the resultant AEMs. Hydroxide conductivity as high as 52.8 mS/cm is obtained for membrane TA-14C-1.21 (IEC = 1.21 mmol/g) with the longest pendant chain at 30 °C, and the conductivity can be increased to 140 mS/cm when the temperature was increased to 80 °C. Moreover, the corresponding water uptake is only 8.6 wt % at 30 °C. In the meantime, the membrane properties can be tuned by precisely regulating the hydrophilic/hydrophobic ratio in the cationic head groups. Compared with AEMs containing triazole and quaternized trimethylammonium head groups, enhanced dimensional stability and mechanical properties are obtained by tuning side-chain chemistry. However, the alkaline stability of the membrane is not as stable as anticipated, probably because of the existence of the triazole ring. Further study will be focused on increasing the alkali stability of the membrane. We envisage that the side-chain-type APEs meditated by click chemistry bearing long hydrophobic side chains pendant to the cationic head groups hold promise as a novel AEMs material.
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei 230026, PR China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Ge
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei 230026, PR China.
authors.forename: Jin
authors.initials: J
authors.lastname: Ran
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei 230026, PR China.
authors.forename: Jibin
authors.initials: J
authors.lastname: Miao
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei 230026, PR China.
authors.forename: Zhengjin
authors.initials: Z
authors.lastname: Yang
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei 230026, PR China.
authors.forename: Tongwen
authors.initials: T
authors.lastname: Xu
keywords: anion-exchange membrane; click chemistry; fuel cells; side-chain type; triazole