Optical flow focusing: Light-induced destabilization of stable liquid threadsReport as inadecuate

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* Corresponding author 1 IPR - Institut de Physique de Rennes 2 LOMA - Laboratoire Ondes et Matière d-Aquitaine

Abstract : Confinement of flowing liquid threads by solid walls makes them stable with respect to the Rayleigh–Plateau instability. We demonstrate here that light can break this stability, by forcing locally the deformation of the liquid interface through thermally-induced Marangoni stresses. Depending upon the confining conditions and fluid properties, this optocapillary deformation either pinches or inflates the thread, which may in both cases lead to its localized fragmentation into droplets. In the pinching regime, the laser beam behaves as a wall-free constriction that flow fo-cuses the thread, leading to successive regimes of single and multiple periodicity. Light-driven local Marangoni stresses may prove an elegant contactless alternative to control reversibly the thread-to-droplet transition for digital microfluidics.

Keywords : Drop and bubble formation Thermocapillary effects Surface-tension-driven instability

Author: Matthieu Robert de Saint Vincent - Hamza Chraibi - Jean-Pierre Delville -

Source: https://hal.archives-ouvertes.fr/


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