Synthesis of metal-loaded poly(aminohexyl)(aminopropyl)silsesquioxane colloids and their self-organization into dendrites

Hydrolytic condensation of N-(6-aminohexyl)aminopropyltrimethoxysilane (AHAPS) in water results in the formation of spherical colloids measuring 40 to 190 nm in diameter and composed of a nearly fully condensed poly(aminohexyl)(aminopropyl)silsesquioxane (PAHAPS) nanostructure containing C-SiO3/2 species. Interaction of Pt and Pd salts with these PAHAPS colloids, followed by chemical reduction, results in the formation of discrete metal nanoparticles measuring ca. 1-2 nm in diameter stabilized within the colloids. Dendrites differing in size and shape are observed to form from aqueous solutions containing PAHAPS colloids loaded with metal salts or metal nanoparticles.