Gold and Silver Nanoparticles Functionalized by the Adsorption of Dialkyl Disulfides.

The formation of three-dimensional self-assembled monolayers (3-D SAMs) generated by the adsorption of -octadecyl disulfide onto colloidal gold and silver nanoparticles is described. The functionalized nanoparticles were characterized by solubility, transmission electron microscopy, ultraviolet-visible spectroscopy, H nuclear magnetic resonance spectroscopy, surface-enhanced Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. On gold nanoparticles, this new functionalization method affords crystalline 3-D SAMs that are indistinct from those prepared by the analogous adsorption of -octadecanethiol. On silver nanoparticles, however, the films derived from -octadecyl disulfide appear to be somewhat less crystalline than those prepared similarly from -octadecanethiol. The origin of this difference is briefly explored and discussed.