基于离子液体的负温度系数柔性温度传感材料的结构调控与性能研究

高分子导电复合材料在温度刺激下具有电阻响应，可用作温度传感材料，在电子皮肤、可穿戴电子等新兴领域具有重要应用。然而，高分子与无机导电纳米粒子复合获得的传感材料，内部导电通路分布不均，导致其温度诱导的结构演变不可控，材料的温度响应信号非单调变化且精度低、稳定性和重复性较差。针对上述瓶颈问题，本项目拟选用离子液体（IL）为传感组分与热塑性聚氨酯（TPU）复合，系统考察IL分子结构与含量对IL分散及材料导电性能、热性能、力学性能和温度传感性能的影响规律，制备单调响应且具有高精度、高稳定性和重复性的负温度系数柔性温度传感材料。此外，针对应变刺激也会导致材料电阻变化，进而干扰温度响应信号这一难题，本项目拟利用3D微纳打印和静电纺丝技术精确构筑可拉伸IL/TPU导电通路，考察导电通路结构与温度传感、应变脱敏性能之间构效关系，明确其物理机制，为制备柔性、可拉伸、可穿戴温度传感材料提供新的思路与方法。

Conductive polymer composites can be used as temperature sensors because of their resistance response to thermal stimulus, which have important applications in some emerging fields such as electronic skins and wearable electronics. However, under thermal stimulus, the sensors composed of polymer and inorganic conductive nanoparticles exhibit uncontrollable structure evolution due to the randomly constructed internal conductive pathways, thus resulting in the non-monotonic electrical signals and poor performance in accuracy, stability and repeatability. In this project, we plan to select ionic liquid (IL) as the sensing component to compound with thermoplastic polyurethane (TPU). The effects of IL molecular structures and contents on IL dispersion and composite properties, including conductive property, thermal property, mechanical property and temperature sensing property, will be systematically investigated. Thus, we plan to design the negative temperature coefficient-based flexible temperature sensors with monotonic electrical response, high precision, high stability and repeatability. Moreover, it is reported that strain stimulus also causes changes in the resistance of composites in the temperature sensing process, thus disturbing temperature sensing signals. To solve this problem, we plan to develop 3D micro-nano printing and electrospinning technologies to accurately construct stretchable IL/TPU conductive pathways. The relationship between the structures of conductive pathways and the temperature sensing and strain desensitization performances of sensors will be investigated to clarify the physical mechanism. Finally, the results of this project can provide new ideas and routes to design flexible, stretchable and wearable temperature sensors.