The Design,Fabrication And Characteristics Of E-textile Strain Sensors

Flexible and wearable electronic devices have attracted significantly increasing attention in recent years for their friendly contact with human body and stable monitoring ability.As one of the most important components of electronic devices,strain sensors are widely used in consumer electronic products,disease and health diagnosis,etc.The preparation of innovative strain sensors is crucial to the development of wearable electronic devices.For wearable electronic devices,besides the excellent electrical performance,the flexibility,comfort and durability of the sensors are also important in the application.The e-textile strain sensor is a kind of e-textile with strain sensing performance which combines the excellent physical properties of the textile such as flexibility,stretch-ability and comfortableness with the sensing of the strain sensor.The physical and electrical characteristics of e-textile sensors are mainly determined by the textile structure and sensitive materials.At present,the formation of a sensitive conductive layer on the surface of fiber,yarn or textile by membrane process is a common idea in the design of flexible fabric strain sensor.In this paper,a flexible e-textile strain sensor was prepared by a simple and ingenious method,and its various properties were studied,and its application in wearable devices was designed and verified.The main work of this paper is as follows:Based on the physical properties of ESD(Electro-Static discharge)Cleanroom Wiper(Polyester interlock-knitted textile)and the excellent electrical properties of reduced graphene oxide(rGO),we prepared a new flexible strain sensor on a traditional polyester fabric using a one-step method that involves the reduction of graphene oxide(GO)using ascorbic acid(L-AA).Effect of the concentration and ratio of graphene oxide(GO)and ascorbic acid(L-AA)on the strain sensing performance was studied.The concentration of graphene oxide(GO)of 1mg / ml and the concentration ratio of graphene oxide(GO)to ascorbic acid(L-AA)of 1: 5 was considered to be the best.The sensor prepared after process optimization showed good negative linear response(GF =-0.84),lower hysteresis(eH = 6.4%),faster response speed(<300ms),sensitive monitoring limit(0.2% strain),and outstanding repeatability and durability(1000 times).Excellent comprehensive performance makes it have considerable potential in wearable applications.In addition,combining the results of performance testing and characterization analysis,a strain-sensitive model is established and the sensitivity mechanism is analyzed for the e-textile strain sensor.Based on the excellent comprehensive performance of the e-textile strain sensor,the wearable applications of this sensor were prospected and verified.Aiming at the durability requirements of the e-textile in wearable applications,the wash-ability of the e-textile strain sensor was studied and it was found that the sensors can still maintain stable strain sensing performance after washing.The e-textile strain sensor has good compatibility with traditional clothing.So the e-textile strain sensors were fixed at multiple points on the clothing to detect and recognize the movements of humanbody.Meanwhile,with the characteristics that the textile could be cut,we modified the devices so that they could withstand these ultra-large strains.Besides the excellent strain performance,the e-textile sensor is also sensitive to humidity.A cooperative sensitive mechanism for respiration detection is proposed and the sensor realizes the efficient and stable real-time detection of respiration signals.