Start Publications From a Bouncing Compound Drop to a Double Emulsion
Attension

From a Bouncing Compound Drop to a Double Emulsion

Year: 2010

Journal: Langmuir, 2010, 26 (14), pp 11680–11685, 20111221

Authors: D. Terwagne†*, T. Gilet‡, N. Vandewalle† and S. Dorbolo†

Organizations: † GRASP, Department of Physics, University of Liege, Liege, Belgium, and ‡ Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

We show that a double emulsion (oil in water in oil) can be created starting from a compound droplet (surfactant solution in oil). The compound drop bounces on a vertically vibrated liquid surface. When the amplitude of the vibration exceeds a threshold value, the oil layer penetrates the water content and leaves a tiny oil droplet within. As this phenomenon occurs at each vigorous impact, the compound drop progressively transforms into a double emulsion. The emulsification threshold, which is observed to depend on the forcing frequency but not on the drop size, is rationalized by investigating the impact of compound drops onto a static liquid surface. The droplet creation occurs when the kinetic energy released at impact is larger than the energy required to deform the compound drop, namely when the Weber number is higher than a given threshold value.