基于卷曲预制棒的热电纤维构筑与结构功能遗传性研究

At present, the fabrication of functional fibers are mainly based on surface modification. However, the physical roughness and chemcial properties of fiber surface may lead to unstability of the functional layer, which will fall off or delaminate during operations such as bending, seriously affecting its functionality. This project intends to fabricate thermoelectric fibers through a novel method called dimension-reduced wiredrawing. One-dimensional nanomaterials as functional layers are patterned and distributed on the surface of a polymer film. The multilayer film is then wound into a preform, and drawn under thermal treatment to prepare a functional fiber. This method overcomes the problem that the interfaces in traditional functional fibers are not firmly bonded. Besides, the functional layer of the two-dimensional thin film morphology can be refined and patterned to facilitate performance characterization, which is conducive to the in-depth study of the energy conversion mechanism of the functionalized fibers. The above fabrication method promise that the functional fibers retain the fine structure of the preform, making the structure and function of the functional layer heritable. The continuous and stable functional fiber fabrication and the structural and functional inheritance of the preform to the functional fiber are the key issues of this project.

目前，功能纤维的制备策略主要是对纤维表面改性再覆盖功能层，然而纤维不平整的表面结构使得功能层在弯折等操作过程中会发生脱落、分层等现象，严重影响纤维功能性的发挥。本项目拟通过降维拉丝的方法长程制备结合稳固的热电纤维，即先在二维薄膜表面图案化分布一维纳米功能层，再卷绕成预制棒结构，最后加热熔融制备出功能纤维。此方法克服了传统功能纤维界面结合不牢固等问题，并且二维薄膜形态的功能层可通过图案化来精细制备，便于性能表征，也有利于对功能层能量转换机制的深入研究；同时此制备方法可以保证功能纤维保留预制棒的精细结构，使得功能层的结构与功能具有遗传性。其中连续稳定的功能纤维的制备和预制棒到功能纤维的结构功能遗传性是本项目的关键问题。

具有能量转换功能的热电纤维可利用人体与环境的温度差将热能转换为电能，实现随身热能富集，但是目前热电纤维的制造与功能层能量转换机制的研究仍面临问题。本项目构筑了同一聚合物预制棒，其中以离子热电材料作为功能层，镓铟液态金属为电极，通过热拉伸及后续电极填充工艺，实现了离子热电纤维的制备，掌握了预制棒到功能纤维成型过程中的结构遗传性，其结构得到保留且聚合物分子链在拉伸下发生重新排列，沿纤维长轴方向发生取向，材料强度得以提高；同时本项目深入研究了平面热电单元的构筑方法，通过刷涂、喷涂、凝胶打印法及自支撑热电薄膜法在平面基底上进行热电材料图案化设计；以卷绕薄膜热电单元、刷涂或湿法纺丝的方式构筑了热电纤维器件，分别深入研究热电单元尺寸对器件性能的影响，及纤维中不同长径比的一维纳米材料和一维纳米材料的取向分布形态对热电性能的影响；此外，本项目以热电纤维基本单元构建热电织物或可拉伸热电器件，研究了不同数量热电单元对热电器件性能的影响，柔性热电器件可穿戴于人体上实现热能到电能的转换，在可穿戴能量转换及收集器件领域具有潜在应用。