Coated colloids with tailored optical properties

Abstract

Tailored optical properties have been imparted to polystyrene (PS) colloids of various sizes by the layer-by-layer (LbL) assembly of silica-coated gold (Au@SiO2) or silica-coated silver (Ag@SiO2) nanoparticles with different shell thicknesses and an electrostatically bridging polyelectrolyte, poly(diallyldimethylammonium chloride) (PDADMAC). The spectral position of the surface plasmon band of the composite colloid spheres is tailored through (i) the type of silica-coated nanoparticles used, (ii) the thickness of the silica shell, and (iii) the number of nanoparticle layers deposited. For thin silica shells ( 18 nm), nanoparticle core-core interparticle interactions are fully prevented and t..