Swimming droplet in 1D geometries, an active Bretherton problem
DE BLOIS, Charlotte
Gulliver (UMR 7083)
Okinawa Institute of Science and Technology Graduate University
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Gulliver (UMR 7083)
Okinawa Institute of Science and Technology Graduate University
DE BLOIS, Charlotte
Gulliver (UMR 7083)
Okinawa Institute of Science and Technology Graduate University
< Reduce
Gulliver (UMR 7083)
Okinawa Institute of Science and Technology Graduate University
Language
en
Article de revue
This item was published in
Soft Matter. 2021-06-04, vol. 17, p. 6646-6660
Royal Society of Chemistry
English Abstract
We investigate experimentally the behavior of self-propelled water-in-oil droplets, confined in capillaries of different square and circular cross-sections. The droplet's activity comes from the formation of swollen micelles ...Read more >
We investigate experimentally the behavior of self-propelled water-in-oil droplets, confined in capillaries of different square and circular cross-sections. The droplet's activity comes from the formation of swollen micelles at its interface. In straight capillaries the velocity of the droplet decreases with increasing confinement. However at very high confinement, the velocity converges toward a non-zero value, so that even very long droplets swim. Stretched circular capillaries are then used to explore even higher confinement. The lubrication layer around the droplet then takes a non-uniform thickness which constitutes a significant difference with usual flow-driven passive droplets. A neck forms at the rear of the droplet, deepens with increasing confinement, and eventually undergoes successive spontaneous splitting events for large enough confinement. Such observations stress the critical role of the activity of the droplet interface on the droplet's behavior under confinement. We then propose an analytical formulation by integrating the interface activity and the swollen micelles transport problem into the classical Bretherton approach. The model accounts for the convergence of the droplet's velocity to a finite value for large confinement, and for the non-classical shape of the lubrication layer. We further discuss on the saturation of the micelles concentration along the interface, which would explain the divergence of the lubrication layer thickness for long enough droplets, eventually leading to the spontaneous droplet division.Read less <
Origin
Hal imported