Study on the synthetic mechanism of monodispersed polystyrene-nickel composite microspheres and its application in facile synthesis of epoxy resin-based anisotropic conductive adhesives

Monodispersed polystyrene-nickel (PS-Ni) composite microspheres were used to enhance the conductivity of epoxy-based anisotropic conductive adhesive (ACA) for the first time. Specifically designed PS-Ni composite microspheres were used as conductive elements to construct anisotropic conductive arrays. The surface microstructure and morphology of the prepared PS-Ni composite microspheres were tuned by controlling the implementation method of electroless plating and concentration of Ni precursor. The structural composition , thermal properties , and electrical properties of PS-Ni composite microspheres were analyzed. In addition, diglycidyl ether of bisphenol-A (DGEBA) epoxy resin and low molecular weight polyamide resin were used as the matrix resin and curing agent , respectively. The optimal process parameters were employed and predicted based on the curing kinetics. A simple strategy was developed for the preparation of anisotropic conductive binders (viz. PS-Ni/EP-ACAs) via physical doping by addition of terminal carboxyl-terminated butadiene acrylonitrile (CTBN) copolymer and additives. PS-Ni/EP-ACAs exhibited satisfactory anisotropic electrical properties in fabricated components due to submicron structures composed of PS-Ni composite microspheres with excellent integrated properties in the anisotropic conducting array. Therefore, the theoretical concept and fabrication mean proposed in this study showed great potential and practical application in large-scale ACAs preparation.