基于连续氢键网络构建的化学键合氨基多膦酸高温质子交换膜的制备及表征

如何提高膦酸基质子交换膜在高温低湿度下的质子电导率是新一代高温膜研制领域的一个研究难点。本项目提出采用氨基三亚甲基三膦酸（ATMP）作为无水质子导电单元，通过膦酰胺键将其化学键合到氨丙基三乙氧基硅烷（APTES）上，然后通过溶胶-凝胶工艺制备化学键合氨基多膦酸聚硅氧烷高温质子交换膜。利用膜中磷、氮的协同效应在膦酸分子之间构建连续氢键网络，通过氢键的断裂与形成，质子可以在膦酸分子之间形成传递，具有"类液体磷酸"特性，提升其在高温低湿度下的质子电导率。主要研究多膦酸基三乙氧基硅烷的反应制备条件对膦酰胺产物结构和化学键合膦酸含量的影响以及不同水解前驱体的配比、溶胶-凝胶温度以及膦酸含量对膜微观结构、热和化学稳定性的影响；重点研究膜中氮、磷、硅比例对连续氢键网络构建的影响以及该膜质子电导率的温度依赖性、湿度依赖性。研究结果将为进一步提高膦酸基质子交换膜的无水质子电导率和综合性能奠定坚实基础。

Currently, it is very difficult to improve proton conductivity of phosphonic acid functionalized polysiloxane proton exchange membrane under high temperature and low humidity. In this research project, firstly, polyphosphonic acid functionalized triethoxysilane will be prepared by phosphoramide bond from the reaction of 3-aminopropyltriethoxysilane (APTES) Amino and Trimethylene Phosphonic Acid (ATMP) which is used as protogenic group. Secondly, polyphosphonic acid functionalized triethoxysilane will be chemically bound to the polysiloxane network in the inorganic-organic hybrid materials by sol-gel process. Thus, continuous hydrogen bond network will be constructed among phosphonic acid in the membrane as a result of synergistic effect of phosphor and nitrogen. Proton can be transported among continuous hydrogen bond network via structure diffusion and, consequently, anhydrous proton conductivity of this membrane will be enhanced owing to its liquid-like properties. The preparation condition of the polyphosphonic acid functionalized triethoxysilane and the effect of the different alkoxysilane precursor, sol-gel condition on the microstructure, thermal stability, chemistry stability and morphology of this membrane will be investigated. The effect of phosphor, nitrogen, silicon content in the membrane to the construction of continuous hydrogen bond network and the proton conductivity temperature and humidity dependence will be carefully evaluated. Research results will establish a firm foundation to more improve comprehensive performance and the anhydrous proton conductivity of phosphonic acid functionalized polysiloxane proton exchange membrane under high temperature and low humidity.