Fast synthesis of nanostructured microspheres of a bridged silsesquioxane via ultrasound-assisted sol-gel processing

Abstract

Microspheres of a nanostructured bridged silsesquioxane were synthesized by employing ultrasound-assisted self-assembly of a bridged monomer via sol-gel processing. The bridged precursor was synthesized from glycidoxypropyl(trimethoxysilane) (GPMS) (2 mol) and cyclohexylamine (1 mol). The main factor controlling the generation of a stable dispersion of microspheres was the time at which the phase separation of the silsesquioxane was produced during the hydrolytic condensation. An appropriate blend of THF/n-hexane as a solvent enabled to rapidly generate a stable dispersion exhibiting a low polydispersity. The mild reaction conditions produced the nanostructuring of the silsesquioxane characterized by a fine structure in SAXS spectrum. Inorganic domains were arranged in a two-dimensional hexagonal system leading to the formation of cavities in the microspheres which could be employed as host-guest systems in advanced technologies. © 2009 WILEY-VCH Verlag GmbH & Co. KCaA.