利用金属有机骨架构建光学各向异性氟化聚合物光波导材料及其特性研究

Fluorinated polymer optical waveguides with high optical anisotropy and low optical loss can offer unique functionalities for the optical transmission and information processing technologies in the future. However, the disorder of polymer chains and grains of fluorinated polymer materials leads to a weak optical macroscopic anisotropy, also, a universal and effective strategy is lacked to align the polymer chain in a highly ordered manner. This project integrates fully the advantages of fluorinated polymer material and Metal-Organic Framework (MOF). MOF is prepared by the self-assembly of metal ions with organic ligands, and features an ordered architecture, microporous, and adsorption of molecules. In the regular microporous MOF, the fluorinated polymer monomer will be adsorbed and then be radically polymerized in an oriented way; thus, owing to the regularity of MOF structure, the obtained polymer chains could be orderly aligned. By removing the rest MOF, a fluorinated polymer waveguide material with high optical anisotropy will be constructed. .This project deeply studies the growth mechanism of MOF structure, while aiming to obtain the long-distance ordered MOF structure by utilizing the surface active effect. More importantly, this project reveals the interaction law between fluorinated polymer monomers and MOF structure, and explores an efficient adsorption mechanism of fluorinated polymer monomers under the introduction of different radically active bifunctional moieties in MOF ligands. Furthermore, by choosing proper initiators in free radical polymerization to increase the orderliness of polymer chains, highly anisotropic polymer materials will be constructed. Last but not least, by optimizing the hot embossing lithograph technique, fluorinated polymer waveguide with high optical anisotropy is going to be fabricated. The target of this project is to provide the theoretical guidance and effective fabrication strategy for the development of novel functional optical materials and devices with high optical anisotropy.

高光学各向异性、低光学损耗的氟化聚合物光波导可实现未来光传输、光信息处理技术所需的独特功能,但氟化聚合物高分子链及晶粒排列的无序性导致其宏观光学各向异性很弱，且缺乏有效的方法对其高分子链有序地排列。本项目充分融合氟化聚合物材料及金属有机骨架（MOF）晶体的优势，借助微孔MOF晶体对聚合物单体分子的吸附，依靠单体分子取向性聚合将MOF结构的有序性转移到聚合物高分子链，从而构建光学各向异性的氟化聚合物光波导材料。拟深入研究MOF结构有序生长的机制，利用表面活性效应获得长程有序MOF；探索氟化聚合物单体分子与MOF相互作用规律，通过引入不同的携带双活性官能团的有机配体来实现单体分子的高效吸附；优选引发剂以提高自由基聚合后高分子链的有序性，构建各向异性的聚合物材料；优化热纳米压印技术改善聚合物晶粒的整体取向，制备高光学各向异性的聚合物光波导；为相关新功能材料及器件的发展提供理论指导及有效制备方式。

高光学各向异性的光波导材料是在未来光传输、光信息处理技术中实现独特功能器件的基础，因此是光学材料的重点研究方向之一。氟化聚合物材料可用于制备低成本的光波导及集成光子器件，其各向异性与聚合物分子结构及分子链取向密切相关，但通常的聚合物分子链以及晶粒是无序排列的，这导致其宏观光学各向异性很弱，而且缺乏有效的方法对其分子链有序地排列。.本项目充分融合氟化聚合物材料和金属有机骨架（MOF）晶体的优势，借助微孔MOF晶体对聚合物单体分子的吸附，依靠单体分子的取向性聚合将MOF结构的有序性转移到聚合物分子链，从而构建光学各向异性的氟化聚合物光波导材料。本项目主要开展了如下几项工作：1）深入研究了MOF结构的有序生长机制，采用溶剂热反应法，利用酸性表面活性剂，制备了结构长程有序的、毫米级的棒状MOF晶体；进一步，实现了交联密度可控的交联性MOF晶体的有序生长；2）探索了氟化聚合物单体分子与MOF相互作用规律，结合分子动力学、密度泛函理论和蒙特卡洛方法，建立了MOF及聚合物单体分子的模型，分析得到实现聚合物单体分子在MOF中高效吸附及扩散的机制；3）研究了客体分子在MOF孔道中取向排列的机制，并通过偏振荧光发射验证了MOF孔道的静电力与位阻效应对发光客体分子取向排列的控制方式；分析了不同极性、大小的氟化聚合物单体分子在MOF孔道中取向聚合的方式，实现了聚合物高分子链在MOF孔道中整体取向排列，制备了高光学各向异性聚合物波导材料；4）研究并提出了聚合物晶粒的整体取向方式，制备了具有光学各向异性的氟化聚合物光学薄膜；基于偏光干涉的机理并结合亮度计法，对聚合物薄膜的光学各向异性做定性及定量的表征；测试结果显示所制备的氟化聚合物光学薄膜的双折射率增大了10倍。本项目研究结果为相关新功能材料及器件的发展提供理论指导及有效制备方式。.在该项目的资助下，发表与本课题相关的论文24篇，其中SCI收录19篇，EI收录3篇；申请国家发明专利6项，培养硕士研究生10名。