Preparation and characterization of polyaniline coated microspheres for potential application in anisotropic conductive film

Monodispersed polyaniline-coated (PANi) microspheres with a mean diameter of 5.174 μm and a 3.53% coefficient of variation were successfully prepared through an in-situ chemical oxidation polymerization of aniline on the surface of high-crosslinked polystyrene-divinylbenzene (PSDVB) particles with the mass ratio of 1: 0.12 between PSDVB particles and aniline. The microspheres were characterized by the scanning electron microscopy (SEM), FTIR and elemental analysis. A very thin layer of polyaniline, about 10.5% in weight, was found to evenly cover on the PSDVB, The microspheres were demonstrated to be thermal stable below 450 °C by thermogravimetric analysis (TGA) measurements and have a bulk conductivity of 6.67 × 10^-3 S.cm^-1 by AC impedance method. The good thermal stability suggested that PANi/PSDVB microspheres could be a promising material to replace the conventional metallic anisotropic conductive film (ACF) particles if the conductivity could be further improved in the future.