The Ultrasonic Welding And Their Applications In Transparent Conductive Film Of Silver Nanowires

Silver nanowires(AgNWs)are widely applicated in transparent electrode,antibacterial,industrial catalysis and other fields due to its excellent properties such as conductivity,thermal,antibacterial properties,biocompatibility and atalytic characteristics.The transparent conductivity films consisting of silver nanowires have good conductivity,high light transmittance,and resistance to bending.However,the silver nanowires transparent conductive film need to add bonding agent because of its bad bonding force with substrate.To solve this problem,we tried to utilize the ultrasonic welding technology to avoid the use of bonding agent.In this paper,liquid polyol reduction method was used to prepare silver nanowire which are averague length of 20 ?m,50-70 nm in diameter.And the low temperature sintering properties of silver nanowires under different atmosphere were studied,the results showed that morphology of silver nanowires did not change obvious in less than 150 ?,and were still consistent with the original.When the temperature rised to 200 ?,the partial melting phenomenon first occured in the contact place of silver nanowires,and the trend was more obvious with the increasing of sintering temperature.The silver nanowires will further fuse into several short nanowires at 250 ?.Until the temperature rises to 300 ?,silver nanowires spheroidizing beginning and their morphology changed from linear into the mixture of short clavite and ball silver nanowires,eventually completely fused into spherical silver nanoparticles.On this basis,compared with the effect of pressure welding and thermal welding,the effect of time,pressure and temperature were studied in process of ultrasonic welding.The rule achieved base on: the welding time and pressure were the main factors influencing the effect of ultrasonic welding,Tiny deformation first occured to silver nanowires under the pressure,and its deformation was proportional to pressure value of the welding.At the start of the ultrasonic welding,the PVP of silver nanowires surface has been removed under the action of ultrasonic wave,which made its surface roughness,the silver nanowires surface began to contact directly,and gradually formed a interconnected conductive network.In the process,the temperature have little impact on the morphology of silver nanowires,but the proper heating can further increase the adhesion of silver nanowires with substrate.The transparent conductivity films of silver nanowires take PET as a substrate,and prepared by spin coating technology.The connection and adhesion between silver nanowires were enhanced by introducing ultrasonic welding,the sheet resistance of the transparent conductive film was decreased by about 50% and the haze was reduced by about 20%.