Morphology and size control of mesoporous ORMOSIL particles prepared from ternary organosilane mixture

Abstract

Tailored mesoporous ORMOSIL particles, having various morphologies such as raspberry shaped, hollow, and rattle type structures, were synthesized by a selective dissolution of organosiloxane networks in ternary ORMOSIL particles preprared using a simple two-step process. The first step, synthesis of monodisperse ORMOSIL particles with multi-layered structure, comprised a one-pot process in an aqueous solution using ternary mixture from three organosilane monomers, 3-aminopropyl-trimethoxysilane (APTMS), vinyl-trimethoxysilane (VTMS), and phenyltrimethoxysilane (PTMS). In the second step, the ORMOSIL particles were treated with a mixture of water and alcohol with mild heating. This mild etching process was employed to dissolve selectively some of organosiloxnae networks within the ORMOSIL particles but not their main silica frameworks, leading to formation of mesoporous particles. Surface roughness, shell thickness, and size of the resultant particles were controlled by manipulating synthetic parameters such as the relative concentration of the silane monomers. Compared to the previously developed synthetic methods, our method offers a simple, economical, and environmentally friendly way to produce complicated mesoporous ORMOSIL particles that can provide several novel properties favorable for practical applications.