Studies On The Preparation And Electrical Properties Of Nanosilver/Graphene Based Flexible Electrically Conductive Adhesives

In recent years,with the rapid development of the electronics industry,flexible electronics has become an important development direction of electronic products.Flexible electronic products are including such as flexible displays,flexible sensors,flexible batteries emerge as the times require.Flexible electronic products require flexible circuits and substrates,and the functions of transmission power and signal are almost unaffected in the process of mechanical deformation such as bending,curling or even folding.In order to adapt to the development of flexible electronic products,it is very important to study and develop a new flexible electronic connecting material with high conductivity and high stability.For this reason,the following work has been carried out from the improvement of conductive fillers.?1?Zinc powder was used as reducing agent and silver nitrate as a precursor,Ag nanodendrites?AgNDs?has been successfully prepared at room temperature.Optimizing the experimental parameters and determining the optimum preparation conditions of AgNDs.The morphology of AgNDs was characterized by SEM,TEM and XRD methods.Electrical conductive adhesives?ECAs?were prepared with epoxy resin as matrix,Ag microflakes?AgMFs?and AgNDs as conductive filler.The results show that the resistivity of conductive adhesives doped with AgNDs can be reduced to 1.74×10^-4?·cm.?2?Thermoplastic polyurethane?TPU?as matrix resins,AgMFs and AgNDs as conductive filler,flexible electrical conductive adhesives?FECAs?with high conductivity and high stability has been prepared.The resistivity can reach 8.28×10^-5?·cm.When the bending radius is 15 mm,the bending cycle is 200 times,and the normalized resistance?R/R₀?is 1.23.When the twist angle is 150^o,the twisting cycle is 150 times,and the R/R₀ is1.77.When the elongation is 12.5%,the tensile cycle is 100 times,and R/R₀ is 10.6.The results show that the FECAs have good conductivity stability in the deformation.?3?Graphene oxide was synthesized used the improved Hummers method.The AgNDs/rGO composites were successfully prepared by one step method using zinc foil as reducing agent.The morphology and structure of AgNDs/r GO composites were characterized by SEM,TEM,XRD and Raman.FECAs were prepared with AgNDs/rGO composites,AgMFs and TPU.The resistivity of FECAs can reach 6.92×10^-5?·cm.When the bending radius is 15 mm,the normalized resistance?R/R₀?is 1.17 after the bending cycle 200 times.After 150 twisting cycles at the distortion angle of 150^o,R/R₀ is 1.65.When the elongation is 12.5%,the tensile cycle is 100 times,and R/R₀ is 7.59.In addition,the FECAs can be used to monitor the movement of human joints?such as fingers,elbows and knees?,and realizes the application of flexible composite materials in sensors.