Table of Contents
Journal of Nanoparticles
Volume 2016 (2016), Article ID 8203260, 9 pages
http://dx.doi.org/10.1155/2016/8203260
Research Article

Improved Synthesis of Nanosized Silica in Water-in-Oil Microemulsions

Department of Chemical Engineering, Wrocław University of Technology, Norwida 4/6, 50-370 Wrocław, Poland

Received 30 November 2015; Accepted 10 February 2016

Academic Editor: Raphael Schneider

Copyright © 2016 Tomasz Koźlecki et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Present contribution describes modified Stöber synthesis of silica nanoparticles in oil-in-water microemulsion, formulated using heptane, 2-ethylhexanol, Tween® 85 nonionic surfactant, and tetraethyl orthosilicate (TEOS). After some specified incubation time, ammonium hydroxide was added and the reaction mixture was stirred for 24 hours at room temperature. Prior to synthesis, pseudoternary diagram was created for oil-rich area and Winsor IV region was identified. These microemulsions were used for synthesis of silica particles. Resulting particles were characterized by dynamic light scattering, electrokinetic measurements, specific surface area measurements, and powder diffraction. Particles’ diameter was ranging between ca. 130 and 500 nm; usually monodisperse distribution was obtained. The specific surface area of nanoparticles was ranging between 250 and 300 m2/g. Notably, productivity per unit volume of solution was 3 to 5 times higher than for previously reported procedures. Our method can be extended, because polymeric materials can be added to dispersed aqueous phase. In our studies, β-cyclodextrin and hydroxyethylcellulose have been used, giving particles between 170 and 422 nm, with the surface area larger than 300 m2/g.