离子液体法构筑石墨烯复合导电纤维及其性能的调控机制

Graphene provides an innovation chance for further improving properties of conductive fibres according to its special nanostructure, excellent conductivity and mechanical property. How to disperse graphene well in solvent and polymer is the difficulty and urgent question for constructing of graphene/cellulose conductive fibers. A novel method is put forward on dispersing graphene using ionic liquids (ILs), dissolving cellulose at the same time, and preparing graphene/cellulose composite conductive fibers via dry-jet wet-spinning. The interactions between IL and graphene, graphene and cellulose, will be studied by molecular simulation. Structures and properties of ILs will be designed and control graphene dispersion, cellulose dissolution, furthermore control three-dimensional conductive network structures, and conductivity and mechanical property of fibers. Three key scientific problems, such as interaction between IL and graphene, interaction mechanism among IL, graphene, and cellulose, relationship between nano-micro structure and conductivity, will be settled. The study will provide scientific foundation for constructing graphene/cellulose composite fibers by ILs, and promote the conductive fibers applied in chemical engineering, materials, and medical fields.

石墨烯因其特殊的纳米结构及优异的导电性和力学性能，为进一步提高复合型导电纤维性能提供了新契机，而如何实现石墨烯在溶剂与高分子聚合物中均匀分散是构筑高性能石墨烯复合导电纤维亟待解决的关键和难点。本项目提出离子液体分散石墨烯、且同时溶解纤维素、经干湿纺丝制备石墨烯/纤维素复合导电纤维的新方法；采用分子模拟探究离子液体-石墨烯、石墨烯-纤维素的相互作用，通过离子液体的结构与性质调控石墨烯分散和纤维素溶解，进而调控石墨烯-纤维素三维导电网络结构的形成、及导电纤维的导电性和力学性能；结合实验、谱学表征和模拟计算，突破离子液体-石墨烯的相互作用机制、离子液体-石墨烯-纤维素的分子作用机理、石墨烯修饰的纤维素纳微结构与导电性能关系三个关键科学问题，为离子液体法构筑石墨烯复合导电纤维的研究提供科学基础，促进其在化工、材料和医药领域的重大应用。

石墨烯和碳纳米管因其特殊的纳米结构及优异的导电性能和力学性能，为构筑复合型导电纤维提供了新契机，而实现石墨烯/碳纳米管在溶剂中的均匀分散性以及探讨碳纳米粒子与高分子聚合物的相互作用，优化石墨烯/碳纳米管与聚合物基体之间的表界面相互作用是构筑高性能碳纳米粒子复合导电纤维亟待解决的关键和难点。本项目建立了二种构筑石墨烯/碳纳米管-聚合物复合导电纤维的新方法。一是以离子液体为溶剂分散石墨烯/碳纳米管，同时溶解纤维素，经干湿纺丝制备石墨烯/碳纳米管-纤维素复合导电纤维；二是以水为溶剂，离子液体为分散剂制备石墨烯/碳纳米管导电分散液，通过湿法涂覆的手段在聚合物纤维表面覆盖碳纳米导电层获得碳纳米导电纤维。采用分子模拟探究离子液体-石墨烯/碳纳米管、石墨烯/碳纳米管-聚合物的相互作用，碳纳米管与聚酯可以通过芳香环与碳纳米管侧壁的π电子发生π-π作用而形成稳定体系，其结合能为-2.78 kal/mol。通过离子液体的结构与性质调控石墨烯/碳纳米管的分散性和纺丝液性能，进而调控导电网络结构的形成及导电纤维的导电性能和力学性能。石墨烯/碳纳米管-纤维素复合导电纤维电导率可达到1195 S/m，比表面积为167 m2/g，体积比电容为709 F/cm3；涂覆型复合导电纤维表面电阻为732 Ω/cm，水性分散液对涤纶纤维润湿功为86.45 mN/m，纤维断裂强度为261 MPa。导电织物方块电阻可达到11.56 Ω/sq，在12 V电压下电发热织物稳态温度可达到140 ℃。结合实验、谱学表征和模拟计算，突破了离子液体-石墨烯/碳纳米管-聚合物的相互作用机制和分子作用机理以及石墨烯/碳纳米管修饰的导电纤维纳微结构与导电性能关系的关键科学问题。这项研究一方面为制备高导电性、良好力学性能和生物相容性的石墨烯/碳纳米管复合导电纤维应用于生物、材料、化工、医药等领域提供理论基础和科学依据，另一方面促进生物质资源和石墨烯/碳纳米管的绿色高值利用，满足人类对环保、可持续发展的需求。