Preparation of Mesoporous Submicrometer Silica Capsules via an Interfacial Sol鈥揋el Process in Inverse Miniemulsion

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• 作者：Zhihai Cao ; Lizi Dong ; Li Li ; Yue Shang ; Dongming Qi ; Qun Lv ; Guorong Shan ; Ulrich Ziener ; Katharina Landfester
• 刊名：Langmuir
• 出版年：2012
• 出版时间：May 1, 2012
• 年：2012
• 卷：28
• 期：17
• 页码：7023-7032
• 全文大小：643K
• 年卷期：v.28,no.17(May 1, 2012)
• ISSN：1520-5827

文摘

Mesoporous silica capsules with submicrometer sizes were successfully prepared via the interfacial hydrolysis and condensation reactions of tetraethoxysilane (TEOS) in inverse miniemulsion by using hydrophilic liquid droplets as template. The inverse miniemulsions containing pH-controlled hydrophilic droplets were first prepared via sonication by using poly(ethylene-co-butylene)-b-poly(ethylene oxide) (P(E/B)-PEO) or SPAN 80 as surfactant. TEOS was directly introduced to the continuous phase of an inverse miniemulsion. The silica shell was formed by the deposition of silica on the surface of droplets. The formation of capsule morphology was confirmed by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The mesoporous structure was verified by nitrogen sorption measurements. The specific surface area could be tuned by the variation of the amount of cetyltrimethylammonium bromide (CTAB) and TEOS, and the pore size by the amount of CTAB. The influences of synthetic parameters on the particle size and morphology were investigated in terms of the amount of CTAB, pH value in the droplets, TEOS amount, surfactant amount, and type of solvent with low polarity. A formation mechanism of silica capsules was proposed.