本项目旨在开发玻璃化转变温度达到370℃、1%热失重达到500℃、可见至近红外光区（400-1000nm）平均透光率85%以上、热膨胀和收缩系数小于20ppm/℃，可在太空使用的透明高分子薄膜，为制备空间薄膜太阳能电池提供基板。通过两个亚甲基桥连的非共轭六元环构建刚性二酐，以三氟甲基提高亚甲基桥的空间稳定性。利用此刚性二酐单体与三氟甲基取代的联苯二胺及其同分异构体共聚获得含氟聚酰亚胺。二胺单体中氨基的位置变化用来调控高分子主链的扭曲，提高薄膜的透光率。通过多个二胺单体的共聚调节透明薄膜的热膨胀和收缩率，获得耐高温、耐低温、耐辐照的聚合物透明基板，为我国发展空间太阳能电池奠定材料基础。

Transparent polymer substrates will be developed for space thin film solar cells. The Tg (glass transition temperature) and Td (1%, thermogravimetic temperature) of the resulting polymer will be above 370℃ and 500℃ respectively. And the average transparency of the obtained films is over 85% from 400-1000nm with coefficient of heat expansion less than 20ppm/℃. Diphenyl dianhydrides containing two methylene bridges between the benzenes will be employed as monomer, in which the methylenes are stabilized with trifluoromethane substitute for the application in space. Isomers of trifluoromethane substituted diamine with diphenyl core are chosen as the comonomer to prepare the fluorine-containing polyimides, in which the positions of the diamine will be modified to twist the polymeric backbone and improve the transparency of the obtained substrates. Multi diamine monomers will be copolymerized to control the coefficient of heat expansion of the substrate. The target transparent polymer films, which exhibit excellent temperature and radiatio n durable properties, will fasten the development of space solar power station in China.