Preparation And Properties Of Wearable Strain Fabric Sensors

Nowadays,flexible strain sensors are getting more and more attention.As a flexible material,yarn has become one of the important components of flexible strain sensors due to its excellent properties such as light texture,common availability,good toughness,stable mechanical properties,easy adsorption,and easy modification.The flexible strain sensor made from yarn has good flexibility,abrasion resistance,and washing resistance,and is suitable for testing in various environments.It has attracted much attention in wearable strain sensing equipment.In this thesis,a flexible stress sensor with high stability and sensitivity is prepared by using yarn as a substrate,coating the yarn surface with a coating liquid,and depositing a conductive polymer.The main research contents were as follows:(1)Using spandex core yarn as the substrate,the prepared carbon nanotube / polypyrrole tube coating solution was coated on the spandex core yarn base material to prepare spandex core yarn / carbon nanotube / polypyrrole tube yarn Line strain sensor.The performance analysis of the prepared material shows that when the coating solution is applied 20 times and dried in a vacuum drying box for 30 minutes after each coating,the obtained spandex core yarn / carbon nanotube / polypyrrole tube yarn is obtained.The linear strain sensor has a resistance change rate of 325% under 5% deformation.The spandex core yarn / carbon nanotube / polypyrrole yarn strain sensor prepared with the increase of tensile deformation increases the resistance change rate.When testing the washing resistance,the conductivity of the spandex core yarn / carbon nanotube / polypyrrole yarn strain sensing sample began to decrease rapidly,then gradually stabilized,and finally stabilized at 40%.The spandex core yarn / carbon nanotube / polypyrrole yarn strain sensing can be stable at different speeds and long-term stretching.The resistance change rate can reach 400% when testing some large movements of the human body such as finger flexion,knee flexion,wrist flexion,etc.,while testing some small human motions such as face bulging,breathing,speaking,etc.It can reach140%.Under various humidity,spandex core yarn / carbon nanotube / polypyrrole tube yarn strain sensor can also work stably.(2)Using stainless steel wire-covered yarn and nickel wire as the substrate,polypyrrole was deposited on the surface of the stainless steel wire-covered yarn as a semiconductor part by electrochemical polymerization,and aluminum was plated on the surface of the nickel wire as a metal part by vacuum coating.Polypyrrole / Al Schottky contact flexible yarn sensor was prepared by partial winding.After 100 times of abrasion test,the polypyrrole /aluminum Schottky contact flexible sensor stabilized the output current signal at 0.36?A.After the second water washing experiment,the output current remained stable at 0.42 ?A.Through the application of polypyrrole / aluminum Schottky contact flexible yarn sensors in various parts of the human body,such as finger flexion,wrist flexion,knee flexion and other movements,polypyrrole / aluminum Schottky contact flexible yarn sensors can maintain stable electricity.Signal output.However,since the polypyrrole / aluminum Schottky contact flexible yarn sensor has limited tensile strain capacity,its sensitivity and signal response are affected,and it is impossible to measure some small movements of the human body.