| In recent years,the flexible strain sensor is widely used in artificial intelligence clothing,flexible electronic devices,human-machine interactions and intelligence robot due to its high sensitivity and high stretchable working strain range.Therefore,the development of the flexible strain sensor is favored by many experts and scholars all over the world.Polymer material are ideal matrix material for flexible strain sensor because of its excellent stretchability and machinability.In this work,Lycra fiber and elastic fabric with high elasticity were selected as the matrix to manufacture the flexible strain sensor by coating method.The sensing behavior of the fiber sensor with coating different nanocomposites layer was compared to analyze the effect of coating layers on the fiber sensing behavior.At the same time,the interfacial force between the conductive filler and the polymer was improved by using the method of noncovalent modification.The sensing behavior of the modified fiber sensor and control fiber sensor was compared,which was illustrated the influence of interfacial force on the sensing behavior of the fiber sensor.The sensing performance of the flexible fabric sensor was studied.The main research work and conclusions of this paper are as follows:(1)Study on the sensing performance of MWCNTs/TPU fiber strain sensorThe MWCNTs/TPU conductive nanocomposites were coated on the surface of Lycra fiber substrate by layer-by-layer(LBL)method.By comparing the sensing performance of fiber sensors with different coating layers,it can be seen that the working stain range increase with coating layer times increasing,the working strain range of fiber sensors increases(the working strain range of fiber sensors with one time of coating is 0-80%;the working strain range of fiber sensor coated five times is 0?240%).However,the sensitivity decreased with the increase of coating layers.The values of GFdecreases from 26.43(1layer)to 8.1(5layers)at a strain of 5%.The fiber sensor can provide stable and repeatable response under different strain,different frequency under cyclic loading.In addition,the sensing mechanism of fiber sensor was studied through modeling.The fiber sensor has the potential to monitor human movement,facial expression and language recognition.(2)Study on the sensing performance of MWCNTs/PCA/TPU fiber strain sensorThe MWCNTs/PCA/TPU conductive nanocomposites were coated on the surface of Lycra fiber substrate by coating method.The effect of interface properties on the sensing behavior of fiber sensors was studied by comparing the sensor performance of modification fiber sensor and control sample.It was found that the electrical conductivity was improved of the modified nanocomposite and the working strain range was increased of the modified fiber sensor.The working strain range of the modified fiber sensor reach 200%,while the control sample just is 75%.However,the initial sensitivity of the modified fiber sensor was decreased,the GF value of 2%MWCNTs/PCA/TPU sample is 5.1,3%MWCNTs/PCA/TPU sample is 3.6.In addition,the modified fiber sensor has better recovery and stability under the cyclic loading.The fiber sensors also have the potential to monitor movement,facial expressions and recognize language.(3)Study on the sensing performance of flexible fabric strain sensorThe MWCNTs/PCA/TPU conductive nanocomposite was coated on the surface of the elastic fabric substrate by coating method.By studying the sensing behavior of the flexible fabric sensor under uniaxial tension,different strain and different frequency,it is known that this flexible fabric sensor has a high sensitivity,and its GF value is 15.8 at the strain 1%,and the working strain range of the flexible fabric sensor is 300%with the filler content of 5%.The sensing mechanism was explained by analyzing fabric structure and fabric sensing performance.In addition,its potential in monitoring human movement was also studied. |
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