Structural Design And Performance Analysis Of A Flexible Piezoresistive Pressure Sensor

With its soft texture,high sensitivity and good wearability,the flexible piezoresistive pressure sensor has broad application prospects in the fields of electronic skin,pulse detection and soft robot haptic sensing.The study of flexible pressure sensors with comprehensive excellent performance and easy preparation process is of great research significance to promote the development of flexible pressure sensors.In this paper,flexible piezoresistive pressure sensors are studied for their structure,preparation process and performance.The main contents are as follows:Firstly,based on the analysis of several different types of flexible piezoresistive pressure sensors mechanism,an uncoated flexible pressure sensor structure is proposed and its performance influencing factors are analyzed.The compressibility performance of several structures with the same width and height is compared,and a flexible pressure sensor is designed using a hemispherical structure made of carbon nanotube/silicone rubber conductive composite as the pressure sensitive layer structure;a finite element model of this sensor is established and its deformation under pressure is simulated;the sensing mechanism of this sensor is described.The effects of different electrode materials and resistivity of the pressure-sensitive layer,thickness of the plane part of the pressure-sensitive layer,and the number of conductive layers of the pressure-sensitive layer on the sensor performance are analyzed.Secondly,a process method for preparing flexible pressure sensors that can be easily and large-area is proposed.By mixing carbon nanotube conductive filler with silicone rubber polymer matrix,the best process parameters for the preparation of conductive composites are explored.The pressure-sensitive layer of the sensor is prepared by combining the mold method with the tap casting method,which can realize the controlled adjustment of the thickness of the plane part of the sensitive layer on the one hand,and the rapid preparation of the pressure-sensitive layer in a large area on the other hand.With Dragon skin 20 silicone rubber as the lower shield layer and Wacker conductive silicone rubber as the electrode layer material,multiple coplanar square material,multiple coplanar square electrode layers can be produced rapidly by one cast.The electrode layer and pressure-sensitive layer are assembled to produce the sensor sample.Finally,the performance of the prepared pressure sensors is tested and analyzed.A pressure sensor performance test platform was built to measure the performance of sensor samples with different parameters,and it is concluded that the dual conductive layer pressure sensor has better linearity and higher sensitivity under medium and high pressure than the single conductive layer pressure sensor.Using the double conductive layer pressure sensor as the test object,its response time,dynamic response,stability and other parameters are measured,and the influence law of ambient temperature,bending deformation and tensile strain on its electrical performance is studied.The practical application scenarios of the prepared flexible pressure sensors are demonstrated.