The mixture of silver nanowires and nanosilver-coated copper micronflakes for electrically conductive adhesives to achieve high electrical conductivity with low percolation threshold

Abstract

For electrically conductive adhesives (ECAs), it is critical to ensure high electrical conductivity and good adhesion reliability for practical applications in electronic products. In this study, high conductivity ECAs at low filler content were achieved by fully utilizing the synergistic effect of nano- and micro-scale fillers. Nanosilver-coated copper micronflakes (Ag@Cus) prepared by an electroless plating method were selected as the main conductive fillers. Silver nanowires (AgNWs) made by a simple one-step polyol method were dispersed as auxiliary conductive fillers in Ag@Cus, providing more possibilities for establishing a large number of conductive bridges. Furthermore, the curing process of matrix resin was predicted based on curing kinetics and was verified by corresponding experiments to determine the optimal curing parameters. The results show that the combination of AgNWs and Ag@Cus in ECAs can significantly reduce the bulk resistivity and percolation threshold compared with the single component. In particular, the bulk resistivity of ECAs filled with AgNWs and Ag@Cus (mass ratio 1:9) is as low as 9.42 × 10−5 Ω cm when the filler content is only 60 wt%.