Preparation of colloidal gold multilayers with 3-(mercaptopropyl)-trimethoxysilane as a linker molecule

A novel strategy to prepare colloidal Au multilayers using 3-(mercaptopropyl)-trimethoxysilane (MPTMS) as a linker molecule was demonstrated. The nanostructure consists of alternate layers of ultrathin thiol-functionalized silica films and Au colloids. In which, a surface sol–gel process was used to prepare the thiol-functionalized silica films. During the self-assembly of Au colloids, a reiterative immersion–rinse approach was used to ensure maximum coverage of isolated Au colloids. The surface coverage of the first colloidal Au monolayer is ca. 45% of a close-packed monolayer. The method yields uniform layer-by-layer growth colloidal Au multilayers through self-assembly at the Au(111) planes, as judged by the ultraviolet–visible (UV–vis) spectroscopic data and the X-ray diffraction (XRD) patterns.