Kinetic Influence of Siliceous Reactions on Structure Formation of Mesoporous Silica Formed via the Co-Structure Directing Agent Route
Kinetic Influence of Siliceous Reactions on Structure Formation of Mesoporous Silica Formed via the Co-Structure Directing Agent Route
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硅质反应对通过共结构导向剂路线形成的介孔二氧化硅结构形成的动力学影响
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发表时间：
2016
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通讯作者：
V. Alfredsson
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作者：
R. Lin;G. Carlström;Q. D. Pham;Michael W Anderson;D. Topgaard;K. Edler;V. Alfredsson
我们调查的机制负责形成的介孔二氧化硅形成与所谓的共结构导向剂（CSDA）路线。该合成依赖于二氧化硅源（原硅酸四乙酯）、阳离子表面活性剂（C18H37N+（CH3）2（CH2）3N+（CH3）3Br2）和CSDA（羧乙基硅烷三醇）之间的相互作用，这导致用羧基官能化的材料。根据合成中HCl的浓度，结构由Fm3m（高pH值）和Fd3m（低pH值）定义，在中间pH值范围内逐渐过渡。在这里，我们的目标是找到由pH值引发的结构变化的起源，并研究硅源的水解对合成的整体动力学的影响。快速过程产生Fm3m，与pH无关，而缓慢过程产生Fd3m。水解步骤是重要的结构控制参数。我们使用29Si NMR研究了二氧化硅和CSDA的交联。交联是相似的，对于…
We investigate the mechanism responsible for the formation of mesoporous silica formed with the so-called costructure directing agent (CSDA) route. The synthesis relies on the interaction between silica source (tetraethylorthosilicate), cationic surfactant (C18H37N+(CH3)2(CH2)3N+(CH3)3Br2), and CSDA (carboxyethylsilanetriol), which results in a material functionalized with carboxylic groups. Depending on the concentration of HCl in the synthesis, the structure is defined by Fm3m (at high pH) and by Fd3m (at low pH), with a gradual transition in the intermediate pH range. Here, we aim at finding the origin for the structural change triggered by pH and investigate the effects of the hydrolysis of the silica source on the overall kinetics of the synthesis. A fast process results in Fm3m, regardless of pH, and a slow process results in Fd3m. The hydrolysis step is the important structural control parameter. We studied the cross-linking of silica and CSDA using 29Si NMR. The cross-linking is similar for th...