Research And Application Of High Sensitivity Flexible Strain Sensor Based On Microcrack Structure

With the development of flexible electronic skin,it is of great significance to study the flexible strain sensor for human motion monitoring,gesture recognition,medical health and human-computer interaction.The crack based flexible strain sensor has been widely concerned in recent years because of its ultra-high sensitivity.Inspired by the scorpion's sensitivity to micro mechanical vibration,a flexible strain sensor with high sensitivity and stability based on micro crack structure is designed and fabricated by using the concept of bionics.In this study,hydroxygraphene conductive materials with excellent conductivity,strong chemical stability and high thermal stability,and UV adhesive substrate materials with strong adhesion and rapid curing performance were selected.Based on the chemical bonding theory,silane coupling agent(KH-550)was used as the "bridging agent" to modify the surface of the substrate.A double hydrogen bond auxiliary structure was formed between the substrate layer and the conductive layer.The substrate,sensitive material and sensing part were bonded by layer by layer dip coating and pre stretching process,and the micro crack sensor was prepared.The mechanism of the sensor is analyzed with the help of micro characterization.The static,dynamic and micro strain characteristics of the sensor are calibrated with the help of tension press and DC resistance tester.The micro crack structure flexible strain sensor has the characteristics of high sensitivity(strain coefficient is 19.65 in the range of 0-30%),long-term stability(more than 10000 cycles),good linearity,negligible drift,fast response time(? 50 ms)and low detection limit(0.10%).It can be directly installed on human skin to realize the motion monitoring of finger joints in different parts,And the application of writing behavior recognition is studied.To sum up,the existence of micro crack structure and double hydrogen bond auxiliary structure solves the problem that flexible strain sensor is difficult to have high sensitivity and high stability at the same time.It has a wide application prospect in the fields of motion monitoring,behavior recognition and human-computer interaction.