Abstract
A AgNO3 solution and a Sn(II)-citrate complex solution were mixed to prepare Ag nanoparticle colloidal solutions. Their nanoparticles had a core-shell structure comprising a metallic Ag core surrounded by a SnO2 shell. The Ag nanoparticles were adsorbed onto epoxy substrates conditioned with either a cationic surfactant solution of stearyl trimethyl ammonium chloride (STAC) or a concentrated solution of cationic polyelectrolyte, poly(diallyldimethylammonium chloride) (PDDA). These conditioners were strongly adsorbed, making the surface charge positive, thereby enhancing the electrostatic adsorption of the negatively charged Ag nanoparticles. The citrate acceleration of the adsorbed Ag nanoparticles increased the Ag/Sn ratio of the adsorbent by dissolving the SnO2 shell of the nanoparticles. Electroless Cu deposition was started at the epoxy substrates catalyzed with Ag nanoparticles. The citrate acceleration process increased the deposition rate of the electroless Cu plating at the initial stage by increasing the Cu nucleation rate.
