Control of silica-alkyltrimethylammonium bromide mesophases with 1,3,5-trialkylbenzenes under acidic conditions.
Control of silica-alkyltrimethylammonium bromide mesophases with 1,3,5-trialkylbenzenes under acidic conditions.
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在酸性条件下用 1,3,5-三烷基苯控制二氧化硅-烷基三甲基溴化铵中间相。
DOI：
10.1021/la901263p
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
T. Okubo
中科院分区：
文献类型：
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作者：
Ayumu Fukuoka;Izumi Kikkawa;Y. Sasaki;Atsushi Shimojima;T. Okubo
本文报道了由正硅酸乙酯（TEOS）、烷基三甲基溴化铵和1，3，5-三烷基苯在酸性条件下形成的SBA型介孔二氧化硅的结构变化。由二氧化硅源和十六烷基三甲基溴化铵（C16 TAB）与不同量的三甲苯（TMB）和三甲苯（TEB）形成Swedish 2D六方中间相，而用三异丙基苯（TIPB）观察到剧烈的结构变化。X射线衍射和透射电子显微镜观察表明，随着TIPB用量的增加，中间相由六方相p6 mm →立方相Pm 3 n →立方相Fm 3 m。因此，TIPB的加入导致优先形成球形胶束，而不是棒状胶束的溶胀。当使用十四烷基三甲基溴化铵（C14 TAB）时，由较少量的TIPB引发类似的结构变化;然而，当使用十八烷基三甲基溴化铵（C18 TAB）时，几乎没有观察到结构变化。这些发现提供了一个更好的理解的作用，1，3，5-三烷基苯在硅烷基三甲基铵中间相的结构控制。
This article reports the structural variation of SBA-type mesostructured silica formed from a mixture of tetraethyl orthosilicate (TEOS), alkyltrimethylammonium bromides, and 1,3,5-trialkylbenzenes under acidic conditions. Swollen 2D hexagonal mesophases were formed from the silica source and hexadecyltrimethylammonium bromide (C16TAB) with varying amounts of trimethylbenzene (TMB) and triethylbenzene (TEB), whereas drastic structural changes were observed with triisopropylbenzene (TIPB). Characterization by X-ray diffraction and transmission electron microscopy observation revealed that the mesophase was changed from hexagonal p6mm to cubic Pm3n to cubic Fm3m with increasing amounts of TIPB. Thus, the addition of TIPB leads to the preferential formation of spherical micelles rather than the swelling of rodlike micelles. When tetradecyltrimethylammonium bomide (C14TAB) was used, similar structural changes were triggered by smaller amounts of TIPB; however, almost no structural change was observed when octadecyltrimethylammonium bromide (C18TAB) was used. These findings provide a better understanding of the roles of 1,3,5-trialkylbenzenes in the structural control of silica-alkyltrimethylammonium mesophases.