Research On Flexible Pressure Sensors Based On PDMS/CNTs

The flexible pressure sensors are lightweight,convenient and highly integrated,they are of great significance in the fields of electronic skin,human-machine interface,medical health and intelligent robots.At present,flexible pressure sensors have been widely studied.According to different application requirements,different conversion principles and different structures are introduced to design high-performance flexible pressure sensors.Some new flexible pressure sensors are even capable of self-power supply,self-healing and biodegradation.At present,the main problems in the research of flexible pressure sensor are high cost,high energy consumption,complex process and difficulty in mass production,which seriously limit the application of flexible pressure sensor in reality.In order to overcome these problems,this paper proposes a flexible pressure sensor based on porous polydimethylsiloxane?PDMS?/multi-walled carbon nanotubes?MWCNTs?,and conducts systematic research on design principles,preparation processes,and sensing characteristics.The main research contents of this article are as follows:?1?Flexible pressure sensor based on PDMS/MWCNTs.A kind of PDMS/MWCNTs composite was prepared by solvent evaporation with ultrasonic dispersion and magnetic stirring.The SEM morphology showed that MWCNTs were uniformly dispersed in PDMS without obvious agglomeration and overlapped with each other to form a conductive network.PDMS/MWCNTs composites were sliced and coated with conductive silver paste as electrodes to prepare a uniform PDMS/MWCNTs flexible pressure sensor.A test platform was built to test and analyze the sensing characteristics of the PDMS/MWCNTs flexible pressure sensor.The test results showed that when MWCNTs was 8 wt%of PDMS,the sensitivity of PDMS/MWCNTs flexible pressure sensor was the highest,0.033 kPa^-1 in the range of 0-10 kPa,with rapid response?response time and recovery time were 47 ms and 85 ms respectively?and stable output after 1000 cycles.?2?Flexible pressure sensor based on porous PDMS/MWCNTs.Based on the above studies,a preparation scheme of porous PDMS/MWCNTs flexible pressure sensor was proposed by taking advantage of the property that ammonium bicarbonate is easily decomposed into gas when heated.In the process of preparing PDMS/MWCNTs composites,the ammonium bicarbonate is doping,and the ammonium bicarbonate is decomposed by heat to produce gas,which is left in the PDMS/MWCNTs composites,thus obtaining the PDMS/MWCNTs flexible pressure sensor with porous structure.Flexible pressure sensors of porous PDMS/MWCNTs with different pore numbers were prepared by doping ammonium bicarbonate with different content,and their sensing characteristics were tested.The test results showed that the sensitivity of the flexible pressure sensor of PDMS/MWCNTs doped with 5 wt%ammonium bicarbonate was the highest,and the sensitivity curve was divided into two stages.The sensitivity of the flexible pressure sensor of PDMS/MWCNTs reached 0.126kPa^-1 in the range of 0-6 kPa,4 times that of the flexible pressure sensor of PDMS/MWCNTs.Sensitivity decreased after pressure was increased to 6 kPa.This scheme significantly improves the sensitivity of the flexible pressure sensor,while the stability,hysteresis,response time and recovery time are almost not affected,and the cost is low,the process is simple,and it is easy for mass production.