Templateless Synthesis of Organosilica Nanotoroids. The Effect of Precursor Concentration

The features of (γ-mercaptopropyl)trimethoxysilane (MPTMS) hydrolytic condensation in alkaline aqueous solutions have been studied. The interrelation between the process time, MPTMS concentration, and structure-related morphological characteristics of the obtained organosilica (silsesquioxane) particles has been determined. It has been shown that toroidal particles are mainly formed at low precursor concentrations (≤2.5 mM) in a solution. The formation kinetics of such nanotoroids has been analyzed, and preliminary data have been obtained on the mechanism of this process. These data have been discussed taking into account the information available from the literature on the structure of silsesquioxanes and the role of disulfide bonds in the formation of anisotropic particles of these compounds.