The conduction development mechanism of silicone-based electrically conductive adhesives

摘要

The conduction development mechanism of silicone-based electrically conductive adhesives (Silo-ECAs) is studied. The reduction of surfactants on silver flakes by hydride in the silicone backbone and the subsequent sintering of the generated silver nanopartides between micron-sized silver flakes are found to be the major contributor to the conductivity development in Silo-ECAs; this is in contrast with the mechanism observed in most polymer-metal ECAs, where the curing shrinkage of the polymer matrix is the major cause of conductivity development. The conductivity development in Silo-ECAs ceases when the polymer curing is completed. Hence, in order to enhance the resulting electrical conductivity, the curing process is prolonged by using a long-chain prepolymer, lowering the platinum catalyst concentration, or adding curing inhibitors. A bulk resistivity of 8.82 x 10~(-5) Ω cm is achieved, which is 55% lower than the best values reported previously for Silo-ECAs.