Characterization of SiO2/Ag composite particles synthesized by in situ reduction and its application in electrically conductive adhesives

In the study, SiO2/Ag composite particles with silver coating onto the surface of silica have been successfully prepared via a novel and facile approach (Oxidation-Reduction Method). In this approach, the SiO2 particles were first modified with 3-ammoniatriethoxysilane (APTES) and glyoxalic acid (GA) through two-step reaction, the aldehyde group ( CHO) were anchored onto the surfaces of silica spheres via electrostatic attraction, these [Ag(TEA)(2)](+) ions in the solution were then reduced by the CHO and coated onto the surface of silica to obtain SiO2/Ag composite particles. The effects of the reaction conditions on silver content and synthetic mechanism had also been discussed. The structure, morphology and optical properties of the SiO2/Ag composite particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis spectroscopy. The results showed the surface of SiO2 was surrounded by pure silver nanoparticles, and the silver nanoparticles had face-centered-cubic structure, the SiO2/Ag composite particles with core-shell morphology and special optical properties. And the small content SiO2/Ag composite particles applied in electrically conductive adhesives (ECAs) improved the electrical bulk resistivity and tensile shear strength. (C) 2015 Elsevier Ltd. All rights reserved.