Electrostatic self-assembly of structured gold nanoparticle/polyhedral oligomeric silsesquioxane (POSS) nanocomposites

Hybrid inorganic/organic composite materials composed of gold nanoparticles of varying size (1.5 and 6.8 nm) and polyhedral oligomeric silsesquioxane (POSS) units were created using electrostatic self-assembly. Carboxylic acid-functionalized mixed monolayer protected gold clusters (MMPCs) were mixed with trimethyl quaternary ammonium-functionalized POSS units, providing well-ordered aggregates. The aggregates were characterized with transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS), revealing an increase in average interparticle spacing upon assembly with POSS. This increase in spacing was shown to influence the surface plasmon resonance band of the larger 6.8 nm An nanoparticles as characterized by UV/Vis spectroscopy.