Effects of silver nano-particles and nano-wires on properties of electrically conductive adhesives

The morphology and content of the silver fillers, resin matrix composition and curing process could significantly affect performance properties of electrically conductive adhesives (ECAs). In this study, the effects of silver nano-particles (NPs) and nano-wires (NWs) were studied on the properties of ECAs, which are under the same curing and aging conditions varied with three kinds of fillers: the mixture of silver micro flakes and NPs at a mass ratio of 17:3, the mixture of silver micro flakes and NWs at a mass ratio of 19:1, and the pure silver micro flakes as the reference sample. Results show that silver NPs might cause the deterioration of electrical conductivity and thermal conductivity in ECAs with the filler weight fraction of 70 wt%, because segregation of silver NPs might increase the average distance between silver micro flakes; but silver NPs could improve the performance properties of ECAs at a filler loading of 85 wt% especially after 200 °C aging. Silver NWs could reduce bulk resistivity of ECAs with the filler weight fraction of 70 wt% from 2.5 × 10⁻³ Ω·cm to 1.8 × 10⁻⁴ Ω·cm. In addition, thermal conductivity and shear strength of ECAs seemed irrelevant to the filler morphology but only correlated positively and negatively with filler loading ratio respectively.