High-Order Multiple Emulsions Formed in Poly(dimethylsiloxane) Microfluidics
High-Order Multiple Emulsions Formed in Poly(dimethylsiloxane) Microfluidics
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DOI：
10.1002/smll.200900569
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发表时间：
2009-09-18
期刊：
影响因子：
13.3
通讯作者：
Weitz, D. A.
中科院分区：
文献类型：
--
作者：
Abate, A. R.;Weitz, D. A.
多重乳剂是液滴的嵌套组。[1，2]一种流体的液滴被封装在第二流体的液滴内，第二流体的液滴本身可以被封装在又一种流体的液滴内。这种“乳液中的乳液”对于许多应用非常有用，包括用于活性物质（例如营养素、杀虫剂、药物和洗涤剂）的包封，以及作为用于合成具有结构化内部的胶体的模板。[3-5]多重乳液通常使用剪切池或多孔膜板大量制备。[6]为了形成多重乳液，将来自一次乳化的液滴与另外的流体一起进料回装置中并再次乳化。这种方法可以非常快速地形成大量的液滴;然而，单个液滴的形成控制不佳。这会产生一些双重乳液，但它们是非常多分散的。[7]对于更高阶的多重乳液，如三重乳液或四重乳液，过多的多分散性使得该方法不切实际。使用玻璃微毛细管装置，可以形成具有受控结构的单分散多重乳液，尽管量小得多。[8，9]与其中许多液滴在几乎没有控制的情况下平行形成的本体方法相反，在微毛细管装置中，液滴在高度控制的情况下单独形成。然而，玻璃装置难以制造，需要手动对准单独的微毛细管。这是劳动密集型的，并且使得装置难以按顺序放大以生产更高阶的多重乳液或并行地生产更大的量。一种上级方法将联合收割机结合微液滴形成的控制与增加的可扩展性。在本文中，我们提出了一个简单的系统，以形成单分散的高阶多重乳液。该方法将微射流液滴形成的控制与
Multiple emulsions are nested sets of drops.[1, 2] Drops of one kind of ffuid are encapsulated inside drops of a second ffuid, which themselves can be encapsulated inside drops of yet another ffuid. Such ‘‘emulsions within emulsions’’are very useful for many applications, including for the encapsulation of actives, such as nutrients, pesticides, drugs, and detergents, and as templates for the synthesis of colloids with structured interiors.[3–5] Multiple emulsions are typically made in bulk using shear cells or porous membrane plates.[6] To form the multiple emulsions, the drops from one emulsification are fed back into the apparatus with additional ffuids and are emulsified again. Such methods can form large quantities of drops very rapidly; however, the individual drop formation is poorly controlled. This produces some double emulsions but they are exceedingly polydisperse.[7] For higher-order multiple emulsions, such as triple emulsions or quadruple emulsions, the excessive polydispersity makes the methods impractical.With glass microcapillary devices, monodisperse multiple emulsions can be formed with controlled structure, albeit in much smaller quantities.[8, 9] As opposed to bulk methods in which many drops are formed in parallel with little control, in microcapillary devices, drops are formed individually with a high degree of control. However, the glass devices are difficult to fabricate, requiring the hand alignment of separate microcapillary tubes. This is labor intensive and makes the devices difficult to scale up sequentially for producing higherorder multiple emulsions or in parallel for producing larger quantities. A superior method would combine the control of microffuidic drop formation with increased scalability. In this paper, we present a simple system to form monodisperse high-order multiple emulsions. This method combines the control of microffuidic drop formation with the