咪唑鎓盐聚芳醚类梳型共聚物的拓扑结构设计及性能调控

项目名称： 咪唑鎓盐聚芳醚类梳型共聚物的拓扑结构设计及性能调控

项目编号： No.21474036

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无机化学

项目作者： 赵成吉

作者单位： 吉林大学

项目金额： 87万元

中文摘要： 基于阴离子交换膜的电化学器件有望摆脱贵金属催化剂Pt的使用，可大幅降低成本，具有重要的应用前景。非季铵化的咪唑鎓盐型阴离子交换膜发展较晚，耐碱性优劣存在很大争议，需要更多实验事实的积累和研究方法学的建立。本项目拟通过对咪唑环C2位和N3位取代基的合理设计，从去质子化效应、共振效应和位阻效应等三个层次对咪唑鎓盐的稳定和降解机理进行系统地研究，回应目前的争论，并筛选出稳定性高的咪唑鎓盐结构。针对阴离子交换膜存在的离子传导率偏低的问题，本项目拟结合RAFT聚合接枝技术，制备三种拓扑结构的咪唑鎓盐聚芳醚类梳型共聚物。通过对聚合物拓扑结构的调控，构筑连通的离子传输通道，提高离子传导率；通过空间延展的憎水性烷基侧链的位阻效应，增强耐碱稳定性；通过对聚合物结构-微相分离形貌-膜性能关系的全面研究，阐明影响碱性聚合物电解质电导率和稳定性的关键结构因素，为设计更加优异、稳定的阴离子交换膜提供借鉴思路。

中文关键词： 聚芳醚；碱性聚合物电解质；梳型共聚物；拓扑结构；耐碱性

英文摘要： Alkaline fuel cells based on anion exchange membranes have received significant interest in recent years, because non-noble metals or inexpensive metal oxides can be used as catalysts to greatly reduce the cost of the device. Recently, polymers with pendant imidazolium cationic groups other than quaternary alkylammonium have been developed due to their relatively high chemical stability, which is largely attributed to the presence of the π conjugated structure. However,degradations of imidazolium cations were also observed under vigorous conditions due to the nucleophilic attack of hydroxide ions to the imidaozole rings. In this project, a variety of C2 and N3-substituted imidazolium cations will be synthesized to find the effective strategy for stabilizing imidazoliums. The influence of substituents on alkaline stability of imidazolium cations and imidazolium-based alkaline polymer electrolytes will be systematically studied, including the competing deprotonations, electronic resonance and sterically hinderance. The project also intends to prepare three types of comb-shaped poly(aryl ether) copolymers by using the RAFT polymerization technique. First,the addition of long alkyl side-chains in the comb-shaped poly(aryl ether) ionomers is expected to enhance the microscopic phase separation between hydrophilic and hydrophobic domains in the membrane, such that the hydroxide ion will locally aggregate and the OH- hopping conduction can become more effective. Second, the long alkyl side chain could signficantly mitigate water swelling of the membrane and reduce the nucleophilic attack of hydroxide at the imidazolium moieties resulting in good alkaline stability of the comb-shaped poly(aryl ether) ionomers. By regulating their topological structure, new anion exchange membranes having micro-phase seperated structure, high ionic conductivity and alkaline stability can be exploited. The findings will provided a general strategy for the rational design of alkaline polymer electrolytes.

英文关键词： Poly(aryl ether);alkaline polymer electrolyte;comb-shaped copolymer;topological structure;alkaline stability