Molecular Dynamics Simulation of the Early Stages of the Synthesis of Periodic Mesoporous Silica
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- 作者：Miguel Jorge ; Jos R. B. Gomes ; M. Natá ; lia D. S. Cordeiro ; Nigel A. Seaton
- 刊名：Journal of Physical Chemistry B
- 出版年：2009
- 出版时间：January 22, 2009
- 年：2009
- 卷：113
- 期：3
- 页码：708-718
- 全文大小：339K
- 年卷期：v.113,no.3(January 22, 2009)
- ISSN：1520-5207
文摘
We present results of detailed atomistic modeling of the early stages of the synthesis of periodic mesoporous silica using molecular dynamics. Our simulations lead to the proposal of a mechanism that validates several previous experimental and modeling studies and answers many controversial issues regarding the synthesis of mesoporous silicas. In particular, we show that anionic silicates interact very strongly with cationic surfactants and significantly adsorb on the surface of micelles, displacing a fraction of previously bound bromide counterions. This induces an increase in micelle size and also enhances silica condensation at the micelle surface. The presence of larger silica aggregates in solution further promotes the growth of micelles and, by binding to surfactant molecules in different micelles, their aggregation. This work demonstrates the crucial role played by silica in influencing, by way of a cooperative templating mechanism, the structure of the eventual liquid-crystal phase, which in turn determines the structure of the porous material.