The control of size and morphology of nanosized silica in Triton X-100 based reverse micelle

Nanosized silica was synthesized by the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in polyoxyethylene (10) tertoctylphenyl ether (Triton X-100)/cyclohexane/ammonia reverse micelle. The effects of [H2O]/[Triton X-100] (R), ammonia concentration on the size and morphology of the spherical silica were investigated thoroughly. The size of silica displayed an interesting variation with the increases of R and ammonia concentration. The smoothness and dispersibility of the spherical silica became better when high R and ammonia concentration were used, but the spherical regularity was not very good. Most interestingly, fiber-like silica has been obtained in the absence of agitation through controlling R and ammonia concentration, and the formation mechanism was discussed. All the results indicate that reverse micelle media possesses the potential to effectively control the size and morphology of the nanomaterials. (C) 2007 Elsevier B.V. All rights reserved.