低渗流阈值超弹导电复合材料的制备及其在柔性压阻传感器中的应用

柔性压阻传感器在电子皮肤、可穿戴医疗监测等领域应用前景广阔。现有结构中敏感层包括弹性变形层和表面导电层两层材料，分别实现对压力的感应及传导。但目前还无法使这两层材料力学性能达到匹配，导致两层间极易剥离，影响器件稳定性及寿命。针对这一问题，本项目提出一种超弹导电复合材料作为单层敏感层，既易变形又导电可独立完成信号传递。通过引入渗流效应，在具有优异超弹性的基体中引入组装有rGO的大长径比磁性Ni-NWs，通过外磁场协同调控两者的排列及分布，实现超低渗流阈值，得到高电导率同时保持了基体超弹性，以此制备新型单层敏感层，从而解决现有压阻传感器中界面失配问题。目前，已初步实现纳米线结构的可控制备及在基体中的排列调控。后续，将系统研究磁场对导电相排列的调控机理及其分布、含量对复合材料电导率等性能的影响规律，结合在压阻传感器中的应用及对稳定性影响的深入研究，将对得到高性能压阻传感器及推广应用产生重要影响。

Flexible pizeoresistive pressure sensors show promising application in various fields, like e-skin, wearable medical monitoring devices and so on. In current piezoresistive sensors, sensing layer consists of the elastic deformable layer and surface conducting layer, which are used to sense and transform the pressure, respectively. However, the match of mechanical property between these two layers has not been solved till now, which would easily cause delamination between these two layers. This will further cause poor stability and short lifetime of the device. To address this issue, one layer of hyperelastic conducting composite material is proposed to transform the signal by itself, which is highly deformable and conductive. Base on percolation theory, Ni-NWs with large length to width ratio assembled on rGO is introduced into hyperelastic matrix with excellent hyperelasticity, and magnetic field is applied to manipulate their alignment and the distribution. In this way, low percolation threshold can be achieved and high conductivity can be obtained while the hyperelasticity of matrix is maintained. The novel single layer of sensing layer will be prepared by this method and the mismatch issue of the piezoresistive sensor can be solved. For now, the controllable preparation and alignment of Ni-NWs has been preliminarily achieved. Later on, systematic study will be performed on the mechanism of controlling assembled conductor alignment by magnetic field. And the influence of conductor on the performance of composite will be investigated in detail, including conductivity and so on. Combing the application of the composite in piezoresistive sensor and intensive study of the effect on its stability, this project will be very meaningful in obtaining high performance piezoresistive sensor and promoting them in real applications.