Particle size control of colloidal suspensions of mesostructured silica

Stable colloidal suspensions of ordered mesostructured silica have been prepared in a concentrated reaction solution under mild acidic conditions using an inorganic silica source and Pluronic P123. This synthesis method results in a high yield, and it is also suitable for studies of formation and growth mechanisms of colloidal mesostructured silica particles. The size of the obtained particles can be controlled within the range of 50-300 nm by varying the amount of water used in the synthesis or addition of salt to the synthesis solution. The pH of the solution is important since it affects the mesoorder of the material, colloidal stability, and product yield. Ordered material was obtained at pH 1.7-5, whereas stable colloidal suspensions were obtained in the range 3-8. A mechanism for formation of the colloidal particles based on a burst nucleation process followed by growth through aggregation is also proposed.