Fabrication And Research Of Multilayer Hybrid Micro-structure Flexible Pressure Sensor

Flexible pressure sensor has been widely concerned because of its application prospect in human motion monitoring,health monitoring and human-computer interaction.Among them,the flexible piezoresistive pressure sensor can convert the pressure signal into the resistance change signal,which has the advantages of simple preparation,low cost and high reliability.However,the balance between high sensitivity and wide detection range is one of the main challenges of flexible piezoresistive pressure sensors.Therefore,the researchers developed a variety of traditional microstructures,including micropattern structures,porous structures,and fiber network structures,to optimize the sensor’s sensitivity and pressure sensing range.However,the improvement of sensing performance of pressure sensors based on traditional microstructures is limited and cannot meet people’s requirements of high sensitivity in a wide range of pressure detection.To solve these problems,we designed and fabricated a flexible pressure sensor with multilayer hybrid microstructures.The sensor is composed of an array of polyvinyl alcohol/polyethylenimine/glycerol/carbon black（PPGC）film with regular micro-protrusion structures on the surface and a fiber network layer of PPGC@carbon nanotubes@carbon fiber（PPGC@CNTs@CF）.The design of hybrid microstructures can be combined with the high sensitivity of the micropattern structure in the low-pressure region and the high sensitivity of the fiber network structure in the medium pressure range.The multi-layer structure design can distribute the pressure load and improve the compressibility of the structure,and increase the pressure sensing range of the sensor.Therefore,based on the multilayered hybrid microstructural design,the sensor can achieve a high sensitivity of 93.97 k Pa^-1in the pressure range of 0-30 k Pa and 31.28 k Pa^-1in the pressure range of 30-200 k Pa.Sensitivity of 4.97k Pa^-1over pressure range of 200-470 k Pa.With a response time of 32 ms and recovery time of 73 ms,the sensor has fast response capability.Compared with previously reported flexible pressure sensors,the sensor has a wider pressure detection range,ultra-high sensitivity and shorter response time.In addition,the sensor has excellent electrical output ability,good durability and long working life.In view of the excellent sensing performance of the sensor,we successfully attached it to the joint and pulse of the human body for detecting various physiological signals of the human body.We also fabricated a 5×5 pixel flexible sensor array for real-time monitoring of spatial pressure distribution.In addition,the sensor has excellent joule thermal performance,which has potential application value in improving human joint injury.