Research On Flexible Piezoresistive Sensor Based On PDMS/SCF/CNT

The piezoresistive polymer flexible sensor is a flexible electronic device that can detect changes in external pressure and transmit a change signal.It has a wide range of application prospects.However,the current development of flexible piezoresistive pressure sensors is not yet perfect,with sensitivity,stability,and repeatability.Both sex and applicability need to be improved.In this paper,a space-based forced assembly method(SCFNA)is proposed,which uses polydimethylsiloxane(PDMS)as a matrix and carbon fiber(SCF)/carbon nanotube(CNT)as a filler to make V-grooved micro and flat surfaces,respectively.Structure,and these two conductive elements are used as the sensitive elements of the sensor;the above two sensitive elements are packaged in the form of face-to-face contact superposition as the sensitive area of the sensor;tightly wrapped with an elastic rubber film to prevent the silicone from entering during the curing process of the package The sensitive area where the microstructure and the plane touch,and ensure that the two sensitive components are in full contact.In order to reduce the resistance fluctuation of the sensor at low pressure,before the sensor is packaged,the pre-stretched PDMS film is used to wrap the sensitive unit tightly,giving the sensor a certain initial resistance value,and improving the stability of the polymer-based flexible sensor and repeatability.Through the optimization of the packing concentration and the thickness of the sensitive element,the performance of the sensor can be improved.The thickness of the sensitive element is 300?m,the concentration of CNTs is 3wt%,the concentration of SCF(4wt%,6wt%,8wt%,10wt%)and the thickness of the sensitive element is 300?m,the concentration of SCF is 8wt%,the concentration of CNT(1wt%,2wt%,3wt%,4wt%)The piezoresistive characteristics of the sensor were analyzed and compared.Finally,the optimized parameters of 3wt%CNTs and 8wt%SCF with a thickness of 300?m were selected to prepare the sensitive element of the flexible sensor,and its sensitivity can be as high as-27.2 ?/N,working range 0?50N.The experimental analysis shows that the sensitivity of the polymer-based flexible sensor with microstructure is 37.7 times that of the polymer-based flexible sensor without microstructure,indicating that building a microstructure is an effective means to improve the sensitivity of the flexible sensor.The sensor performance test results show that in the range of 0?50N,with the increase of pressure,the resistance shows a decreasing trend.In the range of 0?15N,the sensitivity of the polymer-based flexible sensor is-27.2?/N,in the range of 15?50N Within the range,the sensitivity of the polymer-based flexible sensor is-2.4?/N.The repeatability error of the polymer-based piezoresistive flexible sensor is 5.5%,and the stability error is within 6%.The prepared sensor has excellent performance,which provides a new method for preparing a flexible sensor with high flexibility,high sensitivity and small stability error in the future.According to the characteristics of the polymer-based piezoresistive flexible sensor,a smart car seat detection system was designed,and an experimental platform was built,which showed that the measurement error of the flexible sensor test system is within 5%,which can meet the requirements of smart car seat measurement and control At the same time,this type of flexible sensor can also be well used in safety carpets with positioning and quantitative signal detection function.