Research On Fabrication And Performance Of Fully Fabric Flexible Pressure Sensor Based On Conductive Polymer

With the rapid development of electronic products,subversive new technologies such as Internet of things(Io T)and wearable medical devices have emerged in recent years,thus improving people's living standards and quality of life.Wearable systems can measure a wide range of physical,biochemical and environmental signals,which can be measured and quantified by sensors integrated into the human body.Among them,electronic textiles with pressure sensing can convert pressure signals into electrical signals,which has developed into a multi-disciplinary field.Electronic textile is the combination of material science,equipment and system engineering and signal processing.It can be widely used in electronic skin,human-computer interface,physiological signal monitoring and so on.Compared with the pressure sensor based on silicon material,the pressure sensor based on fabric has obvious advantages of softness,reproducibility,easy wearability,washing resistance and high fitting degree.The integration of electronic devices on fabric substrate is the development trend of wearable electronic products.The main content of this paper is based on the fabric as the substrate to integrate flexible pressure sensors,as well as structural design,preparation and application.The research includes the following two parts:(1)Design and fabrication of flexible force sensor based on ploy(3,4-ethylenedioxythiophene)all fabric.Sensitivity and linearity are important indexes of flexible pressure sensor.In order to improve the performance of the sensor,considering the characteristics of natural porous structure and surface obeying Gaussian distribution of non-woven fabric,it is proposed that the piezoresistive layer and bottom electrode are based on non-woven fabric,so that there is a larger contact area under lower pressure,thus the sensing sensitivity and linearity of the device are improved.The piezoresistive layer was prepared by vapor phase polymerization of ploy(3,4-ethylenedioxythiophene)(PEDOT)on the surface of non-woven fabric in vacuum,and the cross electrode prepared on the surface of nonwoven fabric by screen printing method.This process is characterized by simple process and low cost.In addition,the sensor also has the advantages of wide pressure detection range,high linearity,fast response time and high stability.With this detector,various applications in pressure signal detection are realized,including finger bending,respiration,pulse and heart rate.(2)Design and manufacture of flexible pressure sensor based on full fabric.A high performance sensor is prepared by using the natural holes and 3D mesh structure of the fabric as well as the surface roughness.Among them,polypyrrole(PPy)nonwoven composites were prepared by gas phase polymerization of pyrrole monomers on the surface of nonwovens in vacuum.The cross electrode was prepared on the surface of nonwoven fabric by screen printing.Then,the sensitivity,linearity,response time and bending resistance of the sensor are studied,and the application of the sensor in the detection of sound,heart rate,pulse and other physiological signals is studied.To sum up,a full-fabric flexible pressure sensor was prepared based on conductive polymers PEDOT and PPy.Finally,physiological signal detection is realized,which can be used in the fields of intelligent clothing,health care and human monitoring,and expands the application of wearable electronic devices.