Playing with Emulsion Formulation to Control the Perforation of a Freely Expanding Liquid Sheet

Abstract : A single-drop experiment based on the collision of one drop of liquid on a small solid target is used to produce liquid sheets that are visualized with a fast camera. Upon impact, the drop flattens into a sheet that is bounded by a thicker rim and radially expanding in air. Emulsion-based liquid sheets are destabilized through the nucleation of holes that perforate the sheet during its expansion. The holes grow until they merge together and form a web of ligaments, which are then destabilized into drops. We propose the perforation mechanism as a sequence of two necessary steps. The emulsion oil droplets first enter the air/water interface, and then spread at the interface. We show that the formulation of the emulsion is a critical parameter to control the perforation as the addition of salt or amphiphilic copolymers can trigger or completely inhibit the perforation mechanism. We demonstrate that the entering of the droplets at the air/water interface is the limiting step of the mechanism. Thin-film forces such as electrostatic or steric repulsion forces stabilize the thin film formed between the interface and the approaching oil droplets, thus preventing the entering of droplets at the interface and in turn inhibiting the perforation process. We theoretically rationalize the successive steps in the approach and entering of an oil droplet at the film interface and the role of salt and amphiphilic polymer in the different steps.
Type de document :
Article dans une revue
Langmuir, American Chemical Society, 2017, 33 (14), pp.3458-3467. 〈10.1021/acs.langmuir.7b00170〉
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Soumis le : lundi 24 avril 2017 - 18:21:45
Dernière modification le : mardi 10 octobre 2017 - 11:01:16

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Clara Vernay, Laurence Ramos, Alois Würger, Christian Ligoure. Playing with Emulsion Formulation to Control the Perforation of a Freely Expanding Liquid Sheet. Langmuir, American Chemical Society, 2017, 33 (14), pp.3458-3467. 〈10.1021/acs.langmuir.7b00170〉. 〈hal-01513239〉

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