A facile method to prepare a series of SiO2@Au core/shell structured nanoparticles

This paper reports a systematic investigation of the attachment of different sized gold nanoparticles (3.5–32 nm) to the polyethyleneimine (PEI) and 3-aminopropyltrimethoxysilane (APTMS)-functionalized, respectively, surfaces of different sized silica nanoparticles (60–340 nm) at room temperature. Functionalization of the surfaces of silica nanoparticles with PEI or APTMS has a profound influence on the attachment gold nanoparticles. While PEI-functionalized silica surfaces bound the midnanometer gold nanoparticles (13–32 nm), APTMS-functionalized silica surfaces did not. A series of different silica–gold core–shell composites were characterized using transmission electron microscopy (TEM) and UV–vis absorbance spectra.