静电纺聚酰亚胺纳米纤维复合膜的多级结构可控构筑及其性能研究

Electrospun polyimide (PI) nanofibers possess many excellent properties,such as high strength, high modulus and great resistance to high temperature and solvents. However,the versatility of PI nanofibers in pratical applications is severely limited due to its high chemical stability and inertness. Therefore, controllable functionalization of PI nanofibers by molecular design and structural tailoring is proposed to be carried out in thisproject, which aims at improving the interfacial interactions between PI and the functional reagents or nanoparticles. Moreover, PI nanofiber composites with hierarchical structures are proposed to be prepared through the combination of electrospinning and different surface modification techniques, such as chemical plating, layer-by-layer self-assembly and in-situ growth approaches. The structural instability,agglomeration behavior and difficulity in separation and retrieval of nanoparticles can be completely avoided when incorporating them into the newly designed multiscale structured PI nanofiber composites, which can also largely broaden the applications of PI composites in energy and environmental areas. In addition, the relationship of fabrication/processing, structure/morphology, physical properties and functionalization of PI nanofiber composites will be thoroughly explored in this project for obtaining high-performance and multi-functional polyimide nanofiber composites, and also laying a solid practical and theoretical basis for the design and development of other kinds of polymer nanofiber composites.

静电纺聚酰亚胺纳米纤维具有高强高模、耐高温、耐溶剂等特点，但单组分材料的性能往往难以满足实际应用需求，而聚酰亚胺的化学惰性又极大限制了其多功能性。本课题拟从分子结构设计出发制备官能化程度可控的聚酰亚胺电纺纳米纤维，以增强其对功能化组分或纳米颗粒的亲和性，改善其界面相互作用；进一步以官能化聚酰亚胺电纺纤维为基板，借助化学镀、原位生长、层层组装等多种修饰和改性方法实现对聚酰亚胺纳米复合纤维及其膜材料的多级结构构筑和形态调控，克服和解决纳米颗粒结构不稳定、易团聚、不易分离与回收等缺点，并探索复合材料在新能源与环境等领域中的应用。拟深入研究聚酰亚胺纳米纤维的官能化、多层次结构构建和形态调控对复合材料性能的影响，总结和建立该类纳米纤维复合膜材料的电纺丝工艺-结构设计/形态调控-性能和功能性-材料应用之间的内在关系规律和机制，并为其他新型高性能高分子纳米纤维复合材料的设计和开发奠定坚实的基础。

聚酰亚胺因分子链中类梯形的结构而具有高耐热、耐低温性、可调的溶剂稳定性、优异的机械性能和电绝缘性能等优良特性，但其高度刚性也致使材料加工比较困难。因此，本项目从分子结构设计出发，通过便捷的静电纺丝工艺和简易的后处理方法，成功开发了多种具有多级结构的新型聚酰亚胺及其碳纳米纤维复合材料，解决了纳米颗粒易于团聚的难题，实现了其在聚酰亚胺纳米纤维基体内部或表面的均匀分散及强界面相互作用，并探索和拓展了其在新能源领域的潜在应用。主要成果包括：（1）发展了静电纺纳米碳基聚酰亚胺复合纤维新体系，拓展了其在新型高性能锂硫电池和钠离子电池领域的应用；（2）实现了具有三维多孔网状结构的碳纳米纤维基复合材料在电催化领域的应用；（3）开发出具有多级结构的碳纳米复合纤维柔性电极材料，并组装了高性能柔性超级电容器。通过本项目的实施，丰富和发展了聚酰亚胺纳米纤维的多级结构构筑与功能化理论，建立了聚酰亚胺及其碳纳米纤维复合材料结构与性能之间的关系规律，对其他新型聚合物纳米纤维复合材料的设计和开发具有重要的理论和实践指导意义。