Fabrication of PS-DVB@Cu core-shell microsphere for anisotropic conductive adhesives by electroless plating with copper nanoparticles as seeds

Polymer@metal core-shell microspheres are widely used in anisotropic conductive adhesives (ACAs). Styrene-divinylbenzene copolymer (PS-DVB) copper core-shell microspheres (PS-DVB@Cu) with high conductivity and anti-oxidation performance were successfully prepared by combining copper nanoparticles (Cu NPs) and electroless plating copper. The Cu NPs served as catalytic seeds, substituting noble metals to promote electroless deposition . Using environmentally benign ammonia borane as the reductant to replace toxic formaldehyde, the dense copper film was deposited on the surface of PS-DVB microspheres. The thickness of the Cu layer and bulk electrical resistivity of PS-DVB@Cu were tuned by controlling the concentration of the reducing agent. The minimum resistivity of PS-DVB@Cu was 3.27 × 10 −6 Ω·m and merely slightly changed in the air for two months. The prepared PS-DVB@Cu-based ACAs could be effectively applied to anisotropic conductive connections in small-scale circuits with satisfactory anisotropic conductivity.