Formation of mesostructured silica in nonionic fluorinated surfactant systems
Formation of mesostructured silica in nonionic fluorinated surfactant systems
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非离子氟化表面活性剂体系中介孔结构二氧化硅的形成
DOI：
10.1016/j.micromeso.2006.01.003
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发表时间：
2006
影响因子：
5.2
通讯作者：
H. Kunieda
中科院分区：
文献类型：
--
作者：
J. Esquena;C. Rodríguez;C. Solans;H. Kunieda
报道了新型含氟表面活性剂C8F17SO2(C3H7)N(C2H4O)NH(简称C8F17(EO)n)的水相行为及其介孔二氧化硅的制备。C8F17(EO)在水中形成细长的胶束和液晶。采用协同自组装沉淀法制备了介孔二氧化硅，并对其进行了系统的研究，考察了表面活性剂和二氧化硅前驱体(TEOS)浓度、pH值以及聚环氧乙烷链长的影响。用SAXS、氮气吸附和透射电子显微镜对所得材料进行了表征。孔内径较小(⩽35Å)，孔壁较厚(>；20Å)。这种材料具有很高的比表面积(≈1000m2/g)，在很小的表面活性剂浓度(2wt.%)下就能实现这一点，从而产生坚固的厚壁，没有明显的微孔。比表面积在焙烧过程中保持不变，尽管由于二氧化硅的交联会有微小的收缩。在较宽的表面活性剂/二氧化硅摩尔比范围内，d间距似乎不变，介于0.006和1摩尔比之间。当HCl浓度高于0.1M时，得到六方有序(P6 Mm)的介孔，而当HCl浓度低于0.1M时，则得到无序的蠕虫状介孔。得到有序介孔六方二氧化硅的最佳环氧乙烷链长对应于10个环氧乙烷单元。
The aqueous phase behavior and preparation of mesoporous silica by new fluorinated surfactants C8F17SO2(C3H7)N(C2H4O)nH (abbreviated C8F17(EO)n) is reported here. C8F17(EO)nforms elongated micelles and liquid crystals in water. Mesostructured silica was prepared by the cooperative self-assembly precipitation method and a systematic study was carried out, investigating the influence of surfactant and silica precursor (TEOS) concentrations, pH and the effect of poly(ethylene oxide) chain lengths. The resulting materials were characterized by SAXS, nitrogen sorption and TEM. The pore inner diameters are small (⩽35Å) and the pore walls are thick (>20Å). The materials possess high specific surface areas (≈1000m2/g), which are achieved at very small surfactant concentrations (2wt.%), producing robust thick walls with no significant microporosity. The specific surface area is preserved during calcination despite a small shrinkage attributed to silica cross-linking. The d-spacing appeared invariable over a wide range of surfactant/SiO2ratios, between 0.006 and 1 molar ratios. Hexagonal ordered (p6mm) mesopores were formed at HCl concentrations higher than 0.1M, while disordered worm-like mesopores were obtained at HCl concentrations lower than 0.1M. The optimum ethylene oxide chain length to obtain well-ordered mesoporous hexagonal silica corresponded to 10 ethylene oxide units.
影响因子：
56.9
作者：
Zhao, DY;Feng, JL;Stucky, GD
通讯作者：
Stucky, GD