Chanatip Samart and Chatchawan Sookman

pp. 511 - 515

Abstract

Nanoporous silica was applied in controlled releasing experiments. Different physical properties of the nanoporous silica, related to variations of the silica sources, affected the releasing behaviour. Two different silica precursors in nanoporous silica synthesis were investigated, tetraethoxysilane and sodium silicate. The nanoporous silica, which was obtained by tetraethoxysilane, gave the highest surface area (800 m²
/g) and pore volume (1.2 cc/g). On the other hand, the nanoporous
silica obtaining from sodium silicate showed the largest pore size (9 nm). The nanoporous silica with larger pore volume can load a higher amount of indigo carmine, which resulted in a fast release due to the large driving force between the silica particle and media solution. However, the releasing rate was not only affected by the pore volume, but also by the interaction between the silanol groups on the silica surface and molecules of indigo carmine.