title: Controllable preparation and formation mechanism of monodispersed silica particles with binary sizes.
abstract: Monodispersed silica particles with bimodal size distribution were successfully prepared through adding an ethanol (EtOH) solution containing tetraethylorthosilicate (TEOS) dropwise into an ammonia EtOH solution at a constant low rate. The effects of the reaction parameters such as ammonia/ethanol ratio, feeding rate of TEOS solution, reaction temperature, and time on the size and size distribution of the as-obtained particles were investigated. Based on these phenomena, a modified LaMer model of nucleation and growth mechanism was proposed to reasonably explain the formation of the as-obtained silica particles with bimodal size distribution. The as-prepared monodispersed silica particles with bimodal size distribution can be directly fabricated into binary colloidal crystals with small particles surrounding large particles by evaporation-induced cooperative self-assembly. This suggests that the method reported here provides a straightforward and effective route to the in situ fabrication of novel binary colloidal crystals and their replicated patterns in one reaction system.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
authors.forename: Suling
authors.initials: S
authors.lastname: Zhao
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
authors.forename: Huiru
authors.initials: H
authors.lastname: Ma
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Sun
authors.forename: Jianguo
authors.initials: J
authors.lastname: Guan
mesh_terms: D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D012821:Silanes; C040733:tetraethoxysilane; D012822:Silicon Dioxide