Influence of the initial chemical conditions on the rational design of silica particles

Abstract

The influence of the water content in the initial composition on the size of silica particles produced using the Stöber process is well known. We have shown that there are three morphological regimes defined by compositional boundaries. At low water levels (below stoichiometric ratio of water:tetraethoxysilane), very high surface area and aggregated structures are formed; at high water content (>40 wt%) similar structures are also seen. Between these two boundary conditions, discrete particles are formed whose size are dictated by the water content. Within the compositional regime that enables the classical Stöber silica, the structural evolution shows a more rapid attainment of final particle size than the rate of formation of silica supporting the monomer addition hypothesis. The clearer understanding of the role of the initial composition on the output of this synthesis method will be of considerable use for the establishment of reliable reproducible silica production for future industrial adoption.

Improvement of Water Resistance of Hemp Woody Substrates through Deposition of Functionalized Silica Hydrophobic Coating, While Retaining Excellent Moisture Buffering Properties

“…As it has been reported by others (Bogush, Tracy, et al 1988;Sato-Berrú et al 2013;Greasley et al 2016), the particle size peaked for a composition of approximately 33 wt% of water (also plotted in Figure 2.6). The obtained measurements of particle size in this study compared with those of other research groups demonstrates that irrespective of the initial quantities of reagents, similar pattern of size increase and Reprinted with permission from Bourebrab, Oben, et al (2018). Copyright 2018 Springer.…”

“…This suggests that Formulations 1 and 2 were insufficient in water, and therefore the hydrolysis reactions did not go to completion. The materials synthesised from Formulations 12 and over demonstrated multiple phase systems: it is thought that partially reacted TEOS formed aggregated structures rather than discrete particulates, as it can seen from the TEM images h to j in Figure 3.9 by Bourebrab, Oben, et al (2018).…”

“…Extensive characterisation work was carried out in order to understand the underpinning parameters for synthesis of silica Stöber spheres. This chapter is based on the work published in Journal of Sol-Gel Science and Technology (Bourebrab, Oben, et al 2018).…”

“…Peer-reviewed article. (Bourebrab, Oben, et al 2018) Valentin Colson, Marion A. Bourebrab, Olivier Jadeau, Christophe Lanos. (2019).…”

“…• To analyse how the water content influences the size, porosity, and characteristics of the silica particles (part of this work was published by Bourebrab, Oben, et al (2018);…”