Abstract
A rapid process of silica coating of colloidal copper nanoparticles by microwave method was studied. Copper nanoparticles were prepared from CuCl2 aqueous solution using hydrazine as reducing agent and cetyltrimethylammonium bromide and citric acid as stabilizers. Obtained copper nanoparticles having the mean diameter of around 30 nm were surface-treated by 3-aminopropyltriethoxysilane and then surface-coated with silica using tetraethoxysilane or silanol terminated polydimethylsiloxane as silica precursors. The uncoated and silica coated copper nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction measurements. By varying several conditions, Cu nanoparticles could be coated with uniform silica shell with the reaction time, i.e. the microwave irradiation time, of only 5 min, although single core containing core-shell nanoparticels could not be obtained. Conclusively, this microwave method is one of the green processes for its short reaction time.
