Preparation Of Flexible And Breathable Electrodes And Their Wearable Triboelectric Sensing Application

In recent years,flexible electrodes have attracted much attention due to their applications in wearable devices,soft robot and electronic skin.The flexible electrode is composed of a flexible substrate material and a flexible conductive material.Most existing flexible electrodes are fabricated using airtight substrate materials,not meeting the comfort requirements for the long-term wear of devices.To address the above problem,novel flexible and breathable electrodes are need to be developed.This dissertation proposes a strategy to fabricate flexible breathable electrodes by using porous TPU fillm as substrates and conductive network films based on 1D nanowires and 2D nanosheets.We prepare novel flexible breathable electrodes of Ag NWs/TPU and MXene/TPU,and then fabricate the wearable wireless triboelectric sensors based these electrodes.The main research results are as follows:（1）Flexible and breathable Ag NWs/TPU electrodes are fabricated by spraying Ag NWs conductive network layer on the surface of porous TPU substrate prepared by breath figure method.The breathability of the porous TPU film is optimized by regulating various parameters.It is found that the porous TPU films with a TPU concentration of 2.0 wt%,a PEG concentration of 0.20 wt%,scraping film thickness of 200μm and plasma post-treatment time of 6 minutes have the best permeability,which has a water vapor transmission rate of 33.68 mg·cm^-2·h^-1.In addition,breathable electrodes with different surface resistance can be fabricated by adjusting the spraying time of Ag NWs.For the Ag NWs/TPU electrode with a surface resistance of 10Ω/sq,the water vapor transmission and light transmittance of Ag NWs/TPU electrode can reach 21.51 mg·cm^-2·h^-1 and 49%.We constructed a triboelectric sensor which uses Ag NWs/TPU electrode as a triboelectric layer assembled with a polymer triboelectric layer.The triboelectric performance of the device is optimized by selecting different polymer material and adjusting the area and surface resistance of Ag NWs/TPU electrode.It is found that the highest output density can be achieved by using PTFE film as the polymer triboelectric layer and Ag NWs/TPU electrode with electrode area of 1×1 cm² and surface resistance of 5Ω/sq.Moreover,a wearable sensor system is developed with flexible breathable Ag NWs/TPU electrodes attached to the arm to collect feedback signals from skin.The system provides real-time feedback to the touch via LED eventually.（2）MXene/TPU flexible breathable electrode is fabricated by breath figure method and spraying method.The electrode has good conductivity,permeability and extensibility.It can achieve 15.64mg·cm^-2·h^-1 gas permeability while the surface resistance is 10Ω/sq.At the same time,the relative resistance does not change significantly in 25%tensile range.A triboelectric sensor based on MXene/TPU electrode and polymer triboelectric layers has been fabricated.By optimazing various polymer layer and surface resistance of MXene/TPU electrode,the transferred charge,open circuit voltage and short circuit current of the device can be up to 8.55 n C,20.75 V and 911 n A,respectively.Moreover,a wearable wireless control unit based on MXene/TPU flexible breathable electrodes is fabricated.The vector control of a wireless car is realized through the contact feedback of the flexible electrode.