Study on the morphological regulation mechanism of hollow silica microsphere prepared via emulsion droplet template
Study on the morphological regulation mechanism of hollow silica microsphere prepared via emulsion droplet template
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DOI：
10.1016/j.cclet.2022.05.013
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发表时间：
2022-05
影响因子：
9.1
通讯作者：
Chu Zhao;Zhiqing Ge;Zhuoni Jiang;Shuo Yan;Jing Shu;Mozhen Wang;X. Ge
中科院分区：
文献类型：
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作者：
Chu Zhao;Zhiqing Ge;Zhuoni Jiang;Shuo Yan;Jing Shu;Mozhen Wang;X. Ge
空心二氧化硅微球的形貌调控对其性能和应用具有重要意义。本文通过正硅酸乙酯（TEOS）在液体石蜡和TEOS组成的乳状液滴模板界面上的水解缩合反应，再用乙醇溶解石蜡，制备了中空SiO2微球。研究了乳化剂结构和用量、正硅酸乙酯（TEOS）用量、催化剂种类、连续水相中乙醇含量等因素对制备的空心SiO2微球粒径、壳层厚度和形貌的影响。结果表明，正硅酸乙酯与水分子的扩散接触以及正硅酸乙酯在油水界面的水解缩合反应是空心二氧化硅微球合成和形貌调控的两个关键过程。具有合适长度疏水链的阳离子乳化剂是成功合成中空二氧化硅微球的前提。水相中的乙醇含量是决定空心微球平均粒径的主导因素，随着醇水体积比从0增加到0.7，空心微球的平均粒径在96 nm ~ 660 nm之间变化。二氧化硅壁厚随乳化剂的含量和疏水链长度、TEOS含量以及催化剂的活性而变化。软模板的组分会影响硅壁的形貌。以环己烷代替液体石蜡，制备了具有纤维状介孔二氧化硅壁的中空微球。本工作不仅丰富了乳液体系中界面聚合的基础理论，而且为拓展中空二氧化硅微球的形貌和应用提供了思路和方法。
The morphology regulation of hollow silica microspheres is significant for their properties and applications. In this paper, hollow silica microspheres were formed through the hydrolysis and condensation reaction of tetraethyl orthosilicate (TEOS) at the interface of the emulsion droplet templates composed of liquid paraffin and TEOS, followed by dissolving paraffin with ethanol. The effects of various factors including the emulsifier structure and content, TEOS content, catalyst type, and the ethanol content in the continuous water phase on the particle size, shell thickness and morphology of the prepared hollow silica microspheres were studied in detail. The results show that the diffusion and contact of TEOS and water molecules as well as the hydrolysis condensation reaction of TEOS at the oil-water interface are two critical processes for the synthesis and morphological regulation of hollow silica microspheres. Cationic emulsifier with a hydrophobic chain of appropriate length is the prerequisite for the successful synthesis of hollow silica microspheres. The ethanol content in water phase is the dominant factor to determine the average diameter of hollow microspheres, which can vary from 96 nm to 660 nm with the increase of the volume ratio of alcohol-water from 0 to 0.7. The silica wall thickness varies with the content and the hydrophobic chain length of the emulsifier, TEOS content, and the activity of the catalyst. The component of the soft template will affect the morphology of the silica wall. When the liquid paraffin is replaced by cyclohexane, hollow microspheres with fibrous mesoporous silica wall are fabricated. This work not only enriches the basic theory of interfacial polymerization in the emulsion system, but also provides ideas and methods for expanding the morphology and application of hollow silica microspheres.