Spontaneous Cyclic Dimpling in Emulsion Films Due to Surfactant Mass Transfer between the Phases
Spontaneous Cyclic Dimpling in Emulsion Films Due to Surfactant Mass Transfer between the Phases
复制标题
由于相间表面活性剂传质而导致乳液膜中的自发循环凹痕
DOI：
--
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
R. Borwankar
中科院分区：
文献类型：
--
作者：
O. Velev;T. Gurkov;R. Borwankar
摘要在观察油相之间的乳状液膜时，发现了一种有趣的自发循环现象，非离子表面活性剂（Tweens）最初溶解在水相中作为稳定剂。薄膜（典型直径为300 μm）在毛细管中形成，并在反射单色光下照射。在薄膜变薄到它们的平衡厚度之后，凹坑（透镜状较厚的形成物）自发地形成并开始围绕它们的中心生长。当达到一定尺寸时，凹坑形成通向周边的通道并流出，留下平面平行的膜。紧接着，一个新的酒窝开始生长，如此循环，可以持续几个小时。我们已经证明，该过程的驱动力是表面活性剂在相之间的重新分配。我们推测，类似的现象，从耦合的表面活性剂的再分配和界面和流体动力学运动的过程中的膜内，可能是重要的新形成的乳液的稳定性。
Abstract A fascinating spontaneous cyclic phenomenon was encountered during observations of aqueous emulsion films between oil phases, Nonionic surfactants (Tweens) initially dissolved in the water phase were used as stabilizers. The films (with typical diameter of 300 μm) were formed in a capillary and were illuminated in reflected monochromatic light. After the films thin down to their equilibrium thickness, a dimple (lens-shaped thicker formation) spontaneously forms and starts to grow around their center. Upon reaching a certain size the dimple forms a channel to the periphery and flows out, leaving a plane-parallel film behind. Immediately afterward a new dimple starts to grow, and so on. This cyclic process could go on for hours. We have proved that the driving force of the process is the surfactant redistribution between the phases. We presume that similar phenomena, resulting from the coupling of the processes of surfactant redistribution and interfacial and hydrodynamic motion inside the films, could be important for the stability of newly formed emulsions.