Mechanism of formation and nanostructure of Stöber silica particles

Abstract

The formation of silica nano- and microparticles has been studied during growth by the modified Stöber-Fink-Bohn (SFB) method. It has been experimentally found that the density and fractal structure of particles vary with size as they grow from 70 to 2200 nm. We propose a model of particle structure which is a dense primary particle core and is composed of concentric secondary particle shells terminating in dense primary particle layers.

Fabrication of Hollow Silica Particles Using a Self-Assembled Polyethylene Granule as a Template

“…For 2 and 4 hr, d was~320 nm and~410 nm, and the particle size on the surface was getting bigger while smaller particles are still found underneath. In summary, silica coating on the granule underwent a process in which small particles grew on the surface and bigger particles grew on the next layer as the reaction time, in which behavior is similar to colloidal silica growth mechanism as previously reported [38].…”

Structure, Optical and Electric Properties of Opal-Bismuth Silicate Nanocomposites

“…2) testi es its amorphous state with a size of coherently di racting domains of about 3 nm. This value is correspondent to the diameter of silica nuclei that appear at the rst stage of sphere growth as a result of the polymerization of silicon acid monomers [7]. As can be seen from comparison of XRD patterns 1, 2 and 4 presented in Fig.…”

“…An average sphere diameter derived from the growth surface images obtained by X-ray microanalyzer JEOL JXA 8200 (Institute of Physics of NAS of Ukraine) and the Bragg light re ection spectra, as described in the paper [5], was 306 ±15 nm. Average linear sizes of channels, tetrahedral and octahedral pores, calculated accordingly to the relations in the paper [7], were 46, 70, and 120 nm, respectively.…”

“…In order to satisfy the change in molar ratio, the melting of silica spheres should be assumed. According to the shell-like model [7], the silica sphere with a 306 nm diameter consists of spherical core of about 100 nm surrounded by the 30 40 nm spherical silica particles. This structure is porous, of course, and has a rough surface.…”

Designer nanoparticles as efficient nucleation agents in polymer foaming

“…[129][130][131][132][133] The hydrolysis and condensation reactions involved are shown in Figure 2.11. The hydrolysis and condensation of silicon alkoxides is promoted through the introduction of hydroxide ions in the reaction mixture, by the addition of e.g.…”