How emulsified droplets induce the bursting of suspended films of liquid mixtures

Fuente: arXiv
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Main Authors: Delance, Léa, Santanach-Carreras, Enric, Passade-Boupat, Nicolas, Lequeux, François, Talini, Laurence, Verneuil, Emilie
Format: Preprint
Published: 2024
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author Delance, Léa
Santanach-Carreras, Enric
Passade-Boupat, Nicolas
Lequeux, François
Talini, Laurence
Verneuil, Emilie
author_facet Delance, Léa
Santanach-Carreras, Enric
Passade-Boupat, Nicolas
Lequeux, François
Talini, Laurence
Verneuil, Emilie
contents Emulsion droplets of silicone oil (PDMS) are widely used as antifoaming agents but, in the case of non-aqueous foams, the mechanisms responsible for the bursting of the films separating the bubbles remain unclear. We consider a ternary non-aqueous liquid mixture in which PDMS-rich microdroplets are formed by spontaneous emulsification. In order to quantitatively assess the effect of the emulsified microdroplets, we measure the lifetime of sub-micrometer-thick suspended films of these emulsions as well as the time variations of their thickness profiles. We observe that a droplet entering the film reduces its lifetime by inducing a local and fast thinning. In most cases, we ascribe it to the spreading of the drop at one of the film interface with air, which drags the underlying liquid and causes eventually the film to burst rapidly. We explain why, despite slower spreading, more viscous droplets cause films to burst more efficiently. More rarely, microdroplets may bridge the two interfaces of the film, resulting in an even more efficient bursting of the film that we explain.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06169
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle How emulsified droplets induce the bursting of suspended films of liquid mixtures
Delance, Léa
Santanach-Carreras, Enric
Passade-Boupat, Nicolas
Lequeux, François
Talini, Laurence
Verneuil, Emilie
Soft Condensed Matter
Emulsion droplets of silicone oil (PDMS) are widely used as antifoaming agents but, in the case of non-aqueous foams, the mechanisms responsible for the bursting of the films separating the bubbles remain unclear. We consider a ternary non-aqueous liquid mixture in which PDMS-rich microdroplets are formed by spontaneous emulsification. In order to quantitatively assess the effect of the emulsified microdroplets, we measure the lifetime of sub-micrometer-thick suspended films of these emulsions as well as the time variations of their thickness profiles. We observe that a droplet entering the film reduces its lifetime by inducing a local and fast thinning. In most cases, we ascribe it to the spreading of the drop at one of the film interface with air, which drags the underlying liquid and causes eventually the film to burst rapidly. We explain why, despite slower spreading, more viscous droplets cause films to burst more efficiently. More rarely, microdroplets may bridge the two interfaces of the film, resulting in an even more efficient bursting of the film that we explain.
title How emulsified droplets induce the bursting of suspended films of liquid mixtures
topic Soft Condensed Matter
url https://arxiv.org/abs/2406.06169