Some stability criteria for double emulsions
Some stability criteria for double emulsions
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DOI：
10.1021/la971271z
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发表时间：
1998-05-12
期刊：
影响因子：
3.9
通讯作者：
Bibette, J
中科院分区：
文献类型：
--
作者：
Ficheux, MF;Bonakdar, L;Bibette, J
双W/O/W乳液由反相乳液组成，其作为直接乳液液滴分散在水连续相中。本文的目的是探索控制双乳液稳定性的基本规则。通过结合不同浓度的水溶性和油溶性表面活性剂，我们生产出 W/O/W 双乳液。我们确定了导致双乳液演化的两种类型的不稳定性：（i）小内部液滴与球体界面的聚结或（ii）油球内小内部液滴之间的聚结。第一种不稳定性导致内部小液滴完全向外相输送，而第二种不稳定性则不然。我们表明，由于这种前一种不稳定性，与小内部液滴释放相关的动力学显然与外相中的亲水性表面活性剂浓度相关。根据该浓度的值，多重乳液可能会在几个月到几分钟的时间范围内不稳定。我们讨论了抑制或引发这些不稳定性的基本标准，强调了界面膜成分的影响。
Double W/O/W emulsions consist in an inverse emulsion which is dispersed within a water continuous phase as direct emulsion droplets. The aim of this paper is to explore the basic rules that govern the stability of double emulsions. By associating both water- and oil-soluble surfactants in various concentrations, we produce W/O/W double emulsions. We identify two types of instabilities that are responsible for the evolution of double emulsions: (i) coalescence of the small inner droplets with the globule interface or (ii) coalescence between the small inner droplets within the oil globule. The first type of instability leads to a complete delivering of the small inner droplets toward the external phase whereas the second one does not. We show that the kinetics associated with the release of the small inner droplets due to this former instability is clearly related to the hydrophilic surfactant concentration in the external phase. Depending on the value of this concentration, multiple emulsions may be destabilized with a time scale ranging from several months to a few minutes. We discuss the basic criteria which are responsible for the suppression or the starting of these instabilities, emphasizing the influence of the composition of the inter-facial films.