原位自组装构筑仿生层次结构纤维素/石墨烯复合纤维

Developing next-generation conductive, strong and tough woven fiber is highly urgent given their great application potential in the areas of flexible smart wearable devices. Unfortunately, traditional conductive textile fiber always exhibits several disadvantages, first, the electrical and mechanical properties were difficult to be well balanced, second, the duration of conductive properties of the fiber is not good enough, and last, the dress comfort of the textile was far from satisfactory. To overcome those shortcomings above, this project proposed a two-order structure concept to endow the conductive textile fiber with both high electrical conductivity and strong mechanical properties. The first-order conducting structure was constructed through in-situ self-assembly of cellulose and graphene in the co-alkali spinning solution, and the secondary conductive structure was created by the simultaneous coating and further reduction of the graphene oxide sheets. Eventually, the highly conductive, strong and tough textile fiber was successfully realized. Additionally, the mechanism of the exfoliation of intercalated graphite in co-alkali solution, strengthening and toughening of two-dimensional graphene on cellulose fiber was investigated. In the meantime, the theory of synergistic compensation effect of the two-order conductive structure was also revealed in this research. The unique two-order conductive structure of the textile fiber makes it highly competitive as a flexible smart wearable device in the areas of electromagnetic shielding, bio-sensing and Joule heating, etc. We believe this research will provide both theoretical basis and experimental support for the design, development and preparation of conductive fibers for smart textiles.

柔性智能可穿戴是新一代功能型纺织材料的重要发展方向，而制备兼具导电、强韧和可编织特性的纤维是实现以上应用的重要前提。针对目前功能纺织用导电纤维存在的问题：一是电学与力学性能难以兼顾，二是导电效果持续时间短，三是人体穿着舒适度差。本项目拟通过低温共碱溶剂（氢氧化钠/尿素）体系同步实现石墨烯的剥离和纤维素的溶解制备纺丝原液，进一步利用石墨烯/纤维素复合纤维的湿法原位自组装（一级导电结构），氧化石墨烯的同步包覆与还原（二级导电结构），最终实现同时提高复合纤维材料的强度、韧性和导电性能的目的。研究过程将揭示插层石墨在共碱溶液中的剥离机理，阐明二维石墨烯对纤维素纤维的增强增韧机制，提出二级导电结构的协同补偿理论。基于此，结合编织与电子技术将二级结构导电纤维进一步制备成为具有柔性传感，电磁屏蔽，焦耳加热等特性的可穿戴器件，为智能纺织品用导电纤维的设计，开发和制备提供理论依据和实验支持。

通过本项目系列实验的开展，我们提出了一种石墨烯水相分散策略，同时利用碱金属离子吸附的低缺陷石墨烯在水溶液中具有疏松堆砌的特点，在没有任何表面活性剂的情况下，实现了纤维素/石墨烯水相分散液的制备。在该体系中，吸附有无机碱金属离子的石墨烯纳米片在水溶液中呈疏松堆砌，使得碱/尿素溶剂溶解的纤维素分子链能扩散到石墨烯层间，从而使石墨烯在碱金属离子和纤维素分子链的位阻效应下实现稳定分散。通过湿法纺丝，该复合分散液能实现纤维素/石墨烯复合导电纤维的制备，并且分散石墨烯复合纺丝液在凝固浴中通过酸碱中和以及离子扩散实现纤维的制备。均匀分散的石墨烯纳米片不仅提高了纤维的强度和韧性，而且赋予纤维以优秀的导电性和湿度响应性。最终该复合导电纤维被成功应用于湿度传感器中，并且能监测人体的呼吸频率。因此，这种分散策略为低成本、绿色制备高性能石墨烯基复合物开辟了一条新的途径。该项目所提出的在纤维素溶解过程中原位分散无机功能粒子，可以拓展成为一种通用的功能纤维材料的制备方法，通过该方法结合湿法纺丝技术，有望为功能型生物质基纤维的开发和功能集成提供新的思路。.本项目研究按照原计划完成了既定研究任务，获得的实验结果与申请书理论预期较为一致，一定程度上说明了申请书所设计研究方案与技术路线的可行性。在本项目的资助下，在纺织材料领域重要期刊上发表SCI论文7篇。