Self-assembled monolayer mediated silica coating of silver triangular nanoprisms

A novel strategy for coating silver triangular nanoprism with silica shells of defined thickness was demonstrated. The chemical process of silica immobilization was facilitated by the monolayer of 16-mercaptohexadecanoic acid (MHA) on the surface of prism. This layer was proved to be effective in preventing the etching and aggregation of the silver nanoprisms during silica coating reaction when dimethylamine (DMA) was added to the reaction solution. Prismatic core-shell nanostructures were obtained, which exhibited increased surface functionality and improved stability in a variety of organic solvents and high salt aqueous environments. These properties allow the hydrophobicity of such core-shell structures to be modified for their assembly into a compact monolayer over large areas using the LB technique. The method can probably be extended to coat gold and silver nanocrystals of other shapes with silica shells.