An optimized sol–gel synthesis of stable primary equivalent silica particles

Abstract

An optimized synthesis of nanometer silica particles via hydrolysis and condensation of tetraethylorthosilicate (TEOS) is described. At the optimum experimental conditions, homogeneous and stable silica nanoparticles with mean particles size of 7.1 ± 1.9 nm were obtained. The particle size is in a good agreement with primary particles. The size, size distribution (SD) and the yield of silica were controlled by the concentration of the reactants, ammonia feed rate, temperature and mixing mode. The increase in TEOS concentration resulted in bigger and multi-model distributed powder, while high temperature and magnetic agitation produced a highly aggregated powder. However, higher H2O/TEOS ratio and lower ammonia concentration at slower feed rate produced particles in the range of 10-14 nm. It was also found that the concentration of silanol group increased significantly with the decrease in particle size, especially below 40 nm. The optimized technique developed is simple and reproducible, affording a high yield of ∼75% of nanometer silica in a primary size range.

Thermal Effect of Er3+Ions Embedded in Smart Nano-Composite Oxide Material Prepared by Sol-Gel Technique

“…An important effect on the densification processes was achieved by well particle size distribution. Nanostructure phase and a narrow size distribution aid in obtaining dense and homogeneous materials [25,26], these results are compatible with the observed FTIR data.…”

Control of porous structure in flexible silicone aerogels produced from methyltrimethoxysilane (MTMS): the effect of precursor concentration in sol–gel solutions

“…It has been reported [28] that the particle sizes of TEOS silica aerogels change nonlinearly with a increase of the molar ratio of water:TEOS from 1.7:1 to 100:1 (or the concentration of water from 17M t 0.5M). Other studies [29] found that particle size decreased when the molar ratio between water and TEOS increased from 1.3:1 to 55.6:1. However, little is known about the effects of water content on pore sizes in aerogels in both TEOS based silica aerogels and MTMS based silicone aerogels.…”

Study on the Properties and Photoactivity of TiO2(nanorod)-SiO2 Synthesized by Sonication Technique

“…TEOS and ethanol were mixed and stirred for 15 min. Then, NH 3 and H 2 O were added dropwise slowly and carefully while sonication was performed for 2 h. All concentrations of the reactant were calculated based on final volume in the reaction mixture 24 . Sonication process took place in an Ultrasonic Homogenizer (Krisbow model 5510, 40 kHz).…”

“…On the other hand, SiO 2 nanoparticle was prepared by sol-gel methods 24 . If the surface of a larger particle is covered by a layer of fine particles, a core-shell system might be resulted 22 .…”