Systematic preparation of high‐quality colloidal silica particles by sol–gel synthesis using reagents at low temperature

Abstract

AbstractWe propose a new approach to obtain monodisperse submicrometer‐sized colloidal silica particles prepared via a modified Stöber synthesis method, leading to high‐quality spherical particles with a narrow size distribution. The novelty of this work consists in setting, previously to the synthesis reaction, the initial temperature of the reagents at low values (6−14°C) in comparison to the constant laboratory room temperature, while fixing other experimental parameters such as humidity and reagent concentrations. A series of samples of monodisperse colloidal silica particles were prepared, with diameters ranging from 600 to 1000 nm and exhibiting quite narrow particle size distributions. According to our results, it was established that the initial temperature of the reagent solutions constitutes a remarkable parameter, affecting the particle size, shape, and monodispersity. This experimental approach even allows the size tunability for the synthesis of large spherical silica particles in a one‐step process. Moreover, in combination with spin‐coating deposition, the proposed technique greatly favors the formation of ordered arrays of monodisperse silica particles over silicon substrates in areas as large as several mm2. This is ideal for thermal insulators, photonic crystals, nanosphere lithography, and other engineering and industrial applications requiring high‐quality extended arrays of monodisperse silica particles.