Preparation And Application Of Flexible Stress Sensor Based On Carbonaceous Nanoballs@gold With 3D Structure

Wearable electronic devices play a huge role in the real-time monitoring of human health.The current sensing materials all have a relatively complete microscopic conductive network structure which resulting in a generally low sensitivity of flexible stress sensors when detecting micro stress.To solve the problem,this thesis puts forward the idea of preparing the carbonaceous nanoballs composite gold nanostructure.The micro-displacement deformation of the sensing material under stress is improved by adjusting and controlling the microstructure of sensing materials,which realizes highly sensitive for detection of flexible stress sensor.And the finite element analysis is used to verify the relationship between the microstructure of the sensing material and the amount of deformation.The main research contents of this thesis are divided into the following aspects:The CBs are act as skeleton to assist the formation of 3D composite structure in 3D nanospace in this thesis.We prepared a Carbonaceous nanoballs(CBs)@gold(Au)composite material with a three-dimensional(3D)composite structure by a simple preparation method.The 3D composite structure of the CBs@Au composite material was characterized and tested by the Scanning Electron Microscope,Energy Dispersive Spectroscopy,Ultraviolet-visible Spectrophotometer and X-Ray Diffractometer.The sensing material is using filter paper to support the CBs@Au composite material and prepare flexible stress sensor based on the CBs@Au@filter paper with a sandwich-like structure.Based on the three-dimensional composite structure of the CBs@Au composite materials,the flexible stress sensor based on the CBs@Au@filter paper realizes high sensitivity.The flexible stress sensor based on the CBs@Au@filter paper has high sensitivity(S=0.12 KPa^-1,0.1?10 KPa,S=0.085 KPa^-1,10?100 KPa),high stability(>5000loading/Unloading cycles)and fast response(response time 50 ms and recovery time 210ms).We prepared the CBs@Au film stress sensor by using a mask to deposite the CBs@Au composite materials.The electrical performance of the film stress sensor is measured with the same test platform and test range.The sensitivity of the CBs@Au film stress sensor is(S=0.07 KPa^-1,0.1?10 KPa,S=0.016 KPa^-1,10?100 KPa)and fast response(response time40 ms and recovery time 110 ms).Moreover,the CBs@Au film stress sensor can still maintain excellent sensing performance after 5000 times of loading/unloading.The flexible stress sensor based on the CBs@Au@filter paper is used as the core component of the wearable electronic device.It tests the response of the three mechanical forces of pressing,bending and torsion,real-time monitoring human wrist pulse,finger joint movement and joint bending angle,which verify the feasibility of human health monitoring and joint bending angle testing.