Preparation of Monodisperse Silica Ultramicrons
单分散二氧化硅超细颗粒的制备

Preparation of silica ultramicrons was reported by using three different surfactants in reverse micellar systems and by using the conventional Stober method. It was found that in the anionic surfactant-based system (AOT/cyclohexane/NH3(H2O reverse micelles) the particle size increases as the water to surfactant molar ratio(wo) is increased. While in the non-ionic surfactant-based system (TritonX(100/hexano1/cyclohexane/NH3(H2O reverse micelles) the particle size decreases as wo is increased. It seems impossible to prepare SiO2 in cationic surfactant- based reverse micelles, such as CTAB and TOMAC systems. Effects of different system conditions on particle size and shape were studied. The particle size distribution and standard deviation were also compared among different methods. It indicates that the reverse micellar method is more suitable for synthesis of silica particles of diameter below 100 nm with lower standard deviation than the Stober method. But the latter is still a good method for preparing larger silica particles((100nm).