Open Access Open Access  Restricted Access Subscription Access

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


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

Present contribution describes modified Stober 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 300m2/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 300m2/g.
User
Notifications
Font Size

Abstract Views: 89

PDF Views: 1




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

Abstract Views: 89  |  PDF Views: 1

Authors

Tomasz Kozlecki
Department of Chemical Engineering, Wrocław University of Technology, Norwida 4/6, 50-370 Wrocław, Poland
Izabela Polowczyk
Department of Chemical Engineering, Wrocław University of Technology, Norwida 4/6, 50-370 Wrocław, Poland
Anna Bastrzyk
Department of Chemical Engineering, Wrocław University of Technology, Norwida 4/6, 50-370 Wrocław, Poland
Wojciech Sawinski
Department of Chemical Engineering, Wrocław University of Technology, Norwida 4/6, 50-370 Wrocław, Poland

Abstract


Present contribution describes modified Stober 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 300m2/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 300m2/g.