Polymerization, preparation monodisperse silica sols

B. A. Keiser s contribution to this book (the introduction to the section Preparation and Stability of Sols ) constitutes an excellent introduction to silica nucleation, polymerization, and growth in both aqueous and alcoholic systems for the preparation of silica sols. Yoshida s chapter (Chapter 2) focuses on industrial development in the preparation of monodisperse sols from sodium silicate and predicts further progress in the development of silica sols that have shapes other than spherical, such as elongated, fibrous, and platelet. Colloidal silica particles with these shapes show novel properties and open the possibility of new industrial applications. 

SILICA NUCLEATION, POLYMERIZATION, AND GROWTH PREPARATION OF MONODISPERSE SILICA SOLS... 

Hollow silica-alumina composite spheres were prepared by polystyrene (PS) template method as follows. The monodisperse PS particles were prepared by emulsifier-free emulsion polymerization [11], The content of PS particles with the diameter of ca. 200 - 300 nm could be tailored through the addition of ethyl alcohol. Then, 15.0 g of the PS template suspension and 6.75 mL of aqueous L(+)-arginine (0.2325 g, Kanto Chem. Co.) solution were added into 40 mL of ethyl alcohol, and then, 20 mL of aluminium(IV) iso-propoxide (AIP, 0.0057 g, Aldrich) / ethyl alcohol solution was added into the mixed solution, following the addition of 0.1551 mL of tetraethoxysilane (TEOS, Kanto Chem. Co., > 99.9 %). The sol-gel reaction was carried out at 323 K for 17 h, and as-prepared hollow silica-alumina composite spheres could be directly obtained. After drying in a desiccator overnight, the obtained fine powders were calcined at 873 K at heating rate = 0.5 K min ... 

Silica Nucleation, Polymerization, and Growth Preparation of Monodispersed Sols... 

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