以碳纳米管为代表的纳米碳材料的力学和电学性能优异，以蚕丝为代表的生物质聚合物的柔韧性和生物相容性优异。基于纳米碳和蚕丝的复合材料可以结合二者的优势，在柔性电子领域中具有潜在的应用价值。本论文针对柔性可穿戴电子器件对材料的需求，深入研究了纳米碳材料、蚕丝材料及其复合材料的可控制备、结构设计和界面设计，成功构建了柔性致动器、增强纤维和导电纤维。本论文的主要内容和研究成果如下：一、采用化学气相沉积法，实现了碳纳米管垂直阵列的可控制备及其微观结构的调控，该阵列可用于制备连续的碳纳米管薄膜和纤维。进一步研究了该阵列的结构特点和生长机理，为后续与蚕丝复合奠定了基础。二、通过对再生蚕丝材料进行结构设计，实现了再生蚕丝纤维在智能织物领域的应用。采用定向静电纺丝技术，制备了高度取向的再生蚕丝纱线。基于再生蚕丝纱线和汗液接触过程中表面能的变化，构建了汗液驱动的纤维致动器，并将其用于自控温智能衣物。基于再生蚕丝纱线的吸湿性，构建了柔性纤维状湿度传感器，其灵敏度与商业硬质湿度传感器相当。三、制备了具有协同增强效果的碳纳米管-蚕丝复合纤维。利用成分分析、分子模拟等手段探索了复合纤维的增强机理，研究了碳纳米管和丝素蛋白分子之间的界面相互作用及其对复合纤维断裂强度的影响。揭示了界面相互作用对丝素蛋白分子二级结构结晶行为的影响，通过界面调控提高了复合纤维断裂强度。四、制备了纳米碳-蚕丝复合导电纤维并探索了它在可穿戴电子器件中的应用。制备了以碳纳米管纤维为导电芯、以丝素蛋白为绝缘层的导电纤维。利用其优异的导电性和柔性，制得无线充电器件和变色纤维。本论文基于纳米碳材料和蚕丝材料的结构和性质，设计并制备了纳米碳-蚕丝复合增强材料和导电材料，进一步构建了柔性电子器件，为纳米碳材料和蚕丝材料在柔性可穿戴电子领域的实际应用奠定了基础。
Carbon nanotube (CNT), a typical carbon nanomaterial, has excellent mechanical and electrical properties. Silk, a typical biomass polymer, has excellent flexibility, toughness and biocompatibility. Their advantages can be combined in their composites, which can be used in flexible electronics. Based on the requirements for the materials in flexible electronic devices, a deep study of controlled synthesis, structural design and interfacial design for carbon nanomaterials, silk materials and their composites had been carried out. Flexible actuators, strong fibers and conductive wires had been successfully fabricated. The main contents are summarized as follows:1. The controlled synthesis and microstructure regulation of vertically aligned CNT arrays were realized by chemical vapor deposition method. The as-obtained arrays can be used to prepare continuous CNT films and CNT fibers. The structural features and its growth mechanism was studied. This part of work laid foundation for the further combination of CNTs and silk.2. In order to realize the application of regenerated silk fibers in smart textiles, structural design of regenerated silk materials was developed. A highly oriented regenerated silk yarn was prepared by directional electrospinning. A fiber-shaped actuator was fabricated, which can be driven by the change of surface energy during the contact between actuators and sweat, for application in self-controlling smart clothes. Besides, a flexible humidity sensor was developed based on the hygroscopicity of silk, with sensitivity comparable to that of a rigid commercial humidity sensor.3. The fabrication of CNT-silk fibers with synergistic reinforcing effect was demonstrated. The reinforcing mechanism of the CNT-silk fiber was explored by component analysis and molecular dynamics simulation. The interactions between CNT and silk fibroin were studied and the influence of the interaction on the breaking strength of CNT-silk fibers was explored. Furthermore, the interaction can influence the crystallization of the secondary structure in silk fibroin. The breaking strength of CNT-silk fibers can be improved through interfacial regulation.4. The fabrication of CNT-silk based wires for application in wearable electronics was developed. The core-sheath wires were fabricated through wrapping conductive CNT fibers with insulative silk fibroin. Based on the high conductivity and flexibility of CNT-silk based wires, their applications in wireless charging devices and color-changing fibers were developed. Based on the structure and properties of carbon nanomaterials and silk materials, various reinforcing materials, conductive materials and the related flexible electronic devices were fabricated, which laid the foundation for their practical application in flexible and wearable electronics.
