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

• Published in: Journal of sol-gel science and technology 2018, Vol.88 (2), p.430-441
• Main Authors: Bourebrab, Marion A., Oben, Delphine T, Durand, Géraldine G., Taylor, Peter G., Bruce, James I., Bassindale, Alan R., Taylor, Alan
• Format: Article
• Language: English
• Subjects: Boundary conditions; Ceramics; Chemistry and Materials Science; colloids; Composites; Composition; etc.; fibers; Glass; Inorganic Chemistry; Materials Science; Moisture content; Morphology; Nanotechnology; Natural Materials; Optical and Electronic Materials; Organic chemistry; Original Paper: Nano-structured materials (particles; Original Paper: Nano-structured materials (particles, fibers, colloids, composites, etc.); Particle size; Silicon dioxide; Tetraethyl orthosilicate; Water levels
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-018-4821-9

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. Highlights Identification of compositional regimes for formation of discrete silica particles. Influence of composition on morphological characteristics. Differentiation between time to completion of silica formation and establishment of particle size.