Design And Development Of Flexible Stress Sensor Based On Graphene And Silver Nanowire Composite

Flexible and telescopic flexible force-sensitive sensors are attracting more and more attention because they can be easily attached to various complex and irregular surfaces.With the further development of Internet of things technology,artificial intelligence technology,biomechanics,medical measurement and other fields,the demand for flexible force sensors is more urgent.As is known,the piezoresistive flexible force sensor only needs a layer of force sensitive composite material as the sensing unit,and the piezoresistive flexible force sensor has flexible electrode arrangement,simple sensing structure,simple manufacturing process,low cost and is suitable for mass production.Therefore,it is very suitable for the fields of electronic skin,motion sensor,health monitoring and posture analysis,and it is also the object of priority development.Although there have been many reports on the research of flexible stress sensors,there are still many problems in the existing flexible stress sensors,and further research is needed.This paper mainly studies on the research of flexible stress sensor based on graphene and silver nanowire.At present,the research on the piezoresistive flexible stress sensors is mainly focused on the case of large deformation.At this time,the flexible stress sensor has high tensile strength and high sensitivity,but the sensitivity is low under micro deformation(?1%).For example,sound signal acquisition,pulse detection,and heartbeat detection are all under micro-deformation,so this limits the range of applications of such sensors.Aiming at this problem,there is a weak interaction between the mixed conductive particles based on the combination of graphene and silver nanowires.The composites prepared by the mixed conductive particles have the properties of reversible breaking and reconnection after stretching.This paper designs and prepares a new type of high sensitive flexible stress sensor.The specific preparation method is as follows: mixing a certain proportion of graphene oxide(GO)and silver nanowires(Ag NWs),adding hydrazine hydrate to carry out REDOX reaction,and obtaining ultra-high conductivity strain-inducing composite material Ag NWs/RGO,suction filtration Film formation,and then the above composite Ag NWs / RGO was encapsulated by flexible polymer(PDMS),and finally,a flexible stress sensor based on graphene and silver nanowire composite was obtained.In this paper,a circuit for testing the performance of the sensor is built,and the sensitivity,bending performance,stability and frequency response characteristics of the prepared flexible force sensor are tested.The effect of the ratio of graphene and silver nanowires on the sensitivity of the sensor was studied experimentally.The results showed that the ratio of graphene to silver nanowire was 1:4,the sensitivity was the highest,and the piezoresistive coefficient was as high as 1547.The esults of 100 cyclic tensile tests show that the prepared sensor has good stability;The developed sensor can be used to test the physiological characteristic signals of pulse,throat sound and fist clenching,and clear signal waveform can be obtained.The flexible stress sensor has better frequency response characteristics.