噻吩类微孔聚合物的制备及电致变色性质研究

Polymeric electrochromic (PEC) materials have shown great potentials in organic electronics applications such as display device. In this project, two important scientific issues will be further investigated, including the influence of electrolyte ions inserting/deserting process on the electrochromic response speed, and the relationship between polymer polaron state (oxidation or reduction state) and its conjugation length. We propose to synthesize the thiophene derivative monomers with different steric structure configurations, in which the cores are chosen to be tetraphenylmethane, triphenylamine, spirofluorene and so on, and different numbers of thiophene groups are introduced to form the peripheral arms. Conjugated microporous polymers with tunable structures are fabricated as film state through the electropolymerization of monomers by coupling of thiophenes in the peripheral arms. Through adjusting refinedly the pore structure of the obtained polymer film, the electrolyte ions inserting/deserting process can be effectively controlled. Based on this, the influence rule of the pore structure in polymer film on the electrolyte ions inserting/deserting process and the electrochromic response speed will be revealed clearly. Meanwhile, in the system of tetraphenylmethane as the core, a carbon atom with the sp3 hybrid character exists, which can break the conjugation between every two peripheral arms. Thus a series of thiophene polymers with different definite conjugation lengths will be obtained via changing the number of thiophene in the peripheral arms. By combining the theory calculation results of electronic structure and the experimental data, the relationship between polaron state and conjugation length for thiophene polymers can be illuminated, to achieve the theoretic prediction and refined control of electrochromic color change. These researches will provide the theoretical basis and experimental data for the design and fabrication of PEC materials with rapid response speed and controllable colors.

聚合物电致变色（PEC）材料在平面显示器件等领域具有潜在的应用前景。本项目针对电致变色过程中电解质离子嵌入脱出对响应速度的影响以及聚合物极子态（氧化态或还原态）性质与共轭长度的关系等科学问题开展研究。提出以四苯基甲烷、三苯胺、螺芴等为核，在外围支臂上引入不同数目的噻吩基团，获得空间构型各异的噻吩类单体，利用电化学聚合制备结构可控的噻吩类微孔聚合物薄膜。通过对薄膜孔隙结构的精细调节，实现电致变色过程中电解质离子的嵌入脱出的有效控制，揭示薄膜的孔隙结构对电解质离子嵌入脱出过程及电致变色响应速度的影响规律；以四苯基甲烷为核构筑的体系，其中心是sp3杂化的C原子，可打断噻吩支臂之间的共轭，获得一系列共轭长度明确的噻吩类微孔聚合物，结合电子结构计算与实验验证，阐明其极子态性质与共轭长度的关联，实现颜色变化的理论预测与精确调控，为设计和制备快速响应、颜色可控的PEC材料提供理论基础和实验依据。

本项目通过引入不同的中心核调控分子的空间构型，外围接以不同数量的噻吩基团来调节支臂的长度，设计并合成出一系列噻吩类有机单体，进而进行电化学聚合制备微孔聚合物薄膜，并对制备的微孔聚合物薄膜进行电致变色性质的表征，探索微孔聚合物薄膜的孔隙结构对电解质离子嵌入与脱出过程及电致变色响应速度的影响规律。研究发现，共轭微孔聚合物材料存在的孔隙结构有利于离子的嵌入脱出过程，可以普遍提高聚合物的电致变色响应速度，同时共轭微孔聚合物中交联结构的存在则可以改善薄膜的结构稳定性，进一步提高电致变色的循环稳定性；而通过在聚合物结构上直接引入咪唑类离子液体基团，则同样可以提高聚合物材料的响应速度；噻吩支臂长度可以调节微孔聚合物材料的颜色变化及响应速度；将微孔聚合物电致变色材料作为变色层，利用电荷匹配原理成功组装了快速响应、优异循环稳定性的电致变色器件。此外，该类微孔聚合物材料不仅具有优异的电致变色性质，同时表现出较高的电化学储能性能，成功获得了兼具电致变色和储能性质的多功能材料。本项目实施期间，共发表SCI论文29篇，获授权中国发明专利8项，培养硕博研究生7人、博士后2人，参加国内外学术会议14人次，圆满完成项目的预期目标。项目直接经费61万元，目前已使用56.24万元，经审计，经费使用合理。