Synthesizing Silver Nanowire Aerogels And Its Flexible Sensor Applications

With the rapid development of the flexible electronics field,there are higher requirements for materials applied in the field of flexible strain sensing,such as excellent mechanical properties,sensing ability,electrical conductivity,sensitivity,stability and biocompatibility.Silver nanowires have excellent electrical conductivity,mechanical properties and stability,and is widely used in the field of flexible electronics due to its excellent ability to build conductive networks.Most of the existing applications of silver nanowires are concentrated in the field of twodimensional transparent flexible conductive films.In this paper,a threedimensional conductive gel composed of pure silver nanowires is proposed based on the traditional polyol method for preparing silver nanowires.The preparation method of bulk material and the aerogel structure of gel were extracted.The formation mechanism of silver nanowire gel was explored and the related performance of aerogel in the field of flexible stress sensing was characterized.In this paper,the active material SSA was added on the basis of the traditional polyol method to prepare nano-silver wire,and a hydrogel composed of pure nanosilver wire was prepared,and the microstructure of each stage was formed by gelation.Ingredient analysis explores the mechanism of gel growth,and compares the difference between the growth mode of gel and ordinary silver nanowire.We conclude that Ag Cl cubic crystal is firstly formed in the nucleation stage,then in some position that the orientation relationship and dynamics are satisfied will grow several silver nanowires on a single crystal nucleus.After the reaction is completed,the silver line will have many new shapes such as branches and bends.The silver lines of these special structures are entangled with each other so that the macroscopic appearance is hydrogel.The dried aerogel structure was successfully extracted by supercritical drying.The aerogel consisted of 100% Ag with a density of 5.84×10-3 g/cm3,which is about 1/2000 of silver.The resistivity can be up to 7.32×10-2 Ω·m.The flexible stress sensing properties of aerogels prepared under different reactant concentrations were studied.The results show that the relative resistance changecompression strain curve fitting is logarithmic,and the aerogel is under small strain(10%).The sensitivity is up to 6.57,the maximum recoverable compressive deformation is more than 75%,and the low-concentration aerogel has a faster response and recovery time of about 80 ms.The strain cycle stability of the aerogel was tested at 1000-40 cycles under 0-40% compressive strain.The high and low aerogels exhibited 8.25% 、4.48% and 3.09% current drift,respectively,showing good long-term service stability.After 30 days of natural aging in the air,the aerogel relative resistance changes by about 5.54%.In addition,the electromagnetic shielding effectiveness of the gel has been studied.The electromagnetic shielding effectiveness of the high concentration gel is up to 60 d B,which has a good application prospect.