Flexible Pressure Sensor Based On Graphene Polymer Composite Microstructure Deformation Response

As an important part of the detection device,the sensor can convert the received external signals into electrical signals or other required forms of output according to a specific law.Traditional sensors are mainly made of rigid components,which greatly limits the application range of sensors.The emergence of flexible sensors just makes up for this shortcoming.Flexible sensors have great application potential in medical detection and other fields.Sensitivity is an important performance index of the sensor.In order to improve the sensitivity,researchers have carried out in-depth research from the selection of materials,structure design,preparation process selection and other aspects,but there are still some problems such as high cost,complex process and difficult to mass production.Is proposed in this paper,based on graphene-flexible sensor preparation methods of polymer composite materials,by spin coating process parameter adjustment and the application of the template,control the form of the function of surface microstructure of the layer,respectively,the preparation of the resistive and capacitive two different sensing mechanism of the flexible sensor,and testing the overall performance of the two kinds of sensors.The specific research results are as follows:（1）A capacitive flexible tactile pressure sensor based on graphene-polymer composite material was prepared.A functional layer with micro-structure on the surface was prepared using 80 mesh sandpaper as a template,and the capacitive flexible sensor was prepared.The sensitivity of the sensor was 0.512 k Pa-1 in the load range of 0-2.6 k Pa,the response time was260 ms,and the hysteresis characteristic parameter was less than 8%.At the same time,the sensor without microstructure and the sensor with micropyramid structure were prepared for comparison.The test results showed that the sensitivity of the sensor without microstructure was 0.125 k Pa-1 in the load range of 0-2.6 k Pa,and the sensitivity of the sensor with micropyramid structure was 0.307 k Pa-1 in the load range of 0-6.3 k Pa.（2）A resistive flexible tactile pressure sensor based on graphene-polymer composite material was prepared.The resistive flexible pressure sensor is prepared.Using 80,400 and800 mesh sandpaper as templates,functional layers with microstructures on the surface were prepared and used to prepare resistive flexible sensors.The sensitivity of 80 mesh,400 mesh and 800 mesh sandpaper as template was 0.341 k Pa,0.251 k Pa and 0.226 k Pa,respectively,in the load range of 0-1.6 k Pa.The sensor prepared by using 80 mesh sandpaper as template can respond to a small external force of 100 Pa with a resistance change rate of 10%,a response time of 100 ms,a hysteresis characteristic parameter of about 7% and a linearity of 15.5%.（3）The capacitive flexible sensor can be attached to the inside of the finger to detect the size of the force required when grasping the object;Resistive flexible sensor can not only be attached to the inside of the finger to detect pressure,but also attached to the finger knuckle to detect finger bending state.The sensor prepared in this paper has simple process,low cost,high sensitivity and response characteristics,good stability.It can be used for tactile sensing,and has certain reference value for the study of wearable sensors.