Effect analysis of filler sizes on percolation threshold of isotropical conductive adhesives

By varying the concentration of surfactant in reverse micelle system, Ag particles from 10 to 200 nm in average diameter were synthesized, which have been characterized by X-ray diffraction and transmission electron microscopy. Isotropical conductive adhesives (ICAs) were prepared by using Ag particles as conductive fillers. It was found that the percolation threshold of ICAs depends on the filler size, which reaches to 63 wt.% when the filler average particle diameter is 50 nm. Results obtained by theoretical calculation are in good agreement with the experimental results.