“Gold colloids have been homogenously coated with silica using silane coupling agents as a primer to make the gold surface vitreophilic. After adding active silica, the particles are transferred in ethanol for uniform silica coating by using the Stober method. Gold nanoparticles used for this study ranged from 5 nm up to 40 nm with mixed results. Silica condensation can be controlled to produce different silica thicknesses on gold. The main problem while coating smaller particles (5 nm and 10 nm) was the final coagulation or necking of silica after coating the gold surface. The possible causes for this effect are also examined. These composite nanoparticles are then characterized by studying their optical properties particularly absorbance using a fiber optic spectrometer. Such complex but functional particles and structures should have potential applications in optics and other areas”--Abstract, page iii
