The preparation of polystyrene/nickel core-shell particles for anisotropic conductive films (ACFs)

The use of core-shell conductive microspheres as conductive fillers for anisotropic conductive films (ACFs) has broad application prospects for high-precision circuit connections. However, existing preparation methods suffer from environmental pollution and a relatively long processing procedure. Therefore, we propose a bio-inspired, simple, and environmentally friendly method for preparing PS/Ni core-shell conductive particles suitable for ACFs. Specifically, this study utilized the oxidative self-polymerization of dopamine (DA) to modify the surface of polystyrene (PS) microspheres. The catechol groups in polydopamine (PDA) act as both reducing agents and anchor groups for palladium (Pd) atoms to catalyze the electroless nickel plating. Results indicated that the amount of (PDA) on the PS surface and the morphology of the formed nickel-phosphor (Ni[sbnd]P) layer were regulated by adjusting the DA polymerization time and concentrations. The prepared PS-PDA/Ni conducting particles with an average diameter of 2 ± 0.2 μm has a low density (1.5 g/cm³) and can be applied to ACFs. The application of the prepared ACFs was demonstrated by bonding two flexible print circuits (FPC) with a line spacing of 200 μm. Good adhesion, conductivity, and anisotropic properties were observed in the bonded FPC-200s. This study provides useful information for producing suitable conductive particles with easy synthesis for ACFs applications.