A simple method to synthesize multifunctional silica nanocomposites, NPs@SiO2, using polyvinylpyrrolidone (PVP) as a mediator

Abstract

The well-investigated method to prepare various nanoparticles is a thermolysis method in hot organic solutions. These nanoparticles are usually dispersible in nonpolar organic solvents, which sometimes causes problem to overcoat them with silica due to the polar alcoholic solvent in the silica forming process. We have developed a general procedure to incorporate high quality nanoparticles into silica beads. Organic-dispersible nanoparticles do not form precipitates in alcoholic solution in the presence of hydrophilic polyvinylpyrrolidone (PVP), and successive addition of TEOS with a basic catalyst can generate silica coating on nanocrystals. The PVP stabilized nanoparticles can also be easily adsorbed on the amino-functionalized silica bead surface to form interesting core-shell type structures. Many different nanoparticles from the thermolysis can be used in our preparation method, and these multifunctional silica nanocomposites are expected to be utilized in many applied fields where wettability, biocompatibility and ease of surface modification are very critical.