Preparation And Properties Of Microstructured Sensor Based On Silver Nanowires

Sensors,one of the three pillars for information technology,are widely used in various fields.With the continuous progress of society in recent years,wearable electronic devices,real-time health detection,electronic skin and other new technologies emerge continuously,and the development of these fields are inseparable from flexible sensors.In this paper,a flexible piezoresistive sensor based on silver nanowires is fabricated by constructing different microstructures to improve sensor sensitivity,repeatability and reduce process complexity.The main contents and conclusions are as follows:（1）To solve the problem that the elastomer and conductive layer of piezoresistive sensor based on the mechanism of interface contact resistance change are likely to fall off,silver nanowires are directly sprayed on semi-cured PDMS under high pressure,which avoids photolithography and other special processes and reduces the cost.A flexible piezoresistive sensor with slightly raised structure has been successfully fabricated by using simple clay template method,with a sensitivity of 0.78 k Pa^-1in the low pressure range and stability in 1000 working cycles.It can detect pressures as low as 1 Pa in real time with a response time of 100 ms,and can clearly detect the sphygmus pulse signal of the radial artery in the wrist.The sensitivity of the pressure sensor to touch and joint bending is demonstrated by clicking/double clicking the mouse and sliding the mouse pulley.In addition,the sensor can identify human breathing frequency and mode,showing broad application prospects in disease prevention,habit correction and other clinical medicine.（2）To further improve the sensitivity of the sensor,the template method was used to construct a smaller micron wrinkle structure.By changing the processing time of UVO,the amount of pre-strain,the thickness of PDMS and other processing conditions,the influence of different processes on the wrinkle structure was studied.Then,the piezoresistive sensors were fabricated by using wrinkled conductive PDMS formed under different conditions,and the effect of wavelength amplitude ratio of specific wrinkled structures on sensor sensitivity was studied.The sensor with the largest microstructural wavelength amplitude ratio has the highest sensitivity,which is 2.588 k Pa^-1.The sensor also shows a fairly low detectable pressure limit（1 Pa）,fast response time（<10 ms）,a wide pressure detection range（1Pa-20 k Pa）,and good cycle stability over 3000 cycles.It can monitor human activities such as touch recognition,muscle contraction detection,joint activity detection,voice recognition and so on,showing broad application prospects in disease diagnosis and various wearable devices.