Enhanced interfacial deformation in a Marangoni flow: A measure of the dynamical surface tension

Once a drop of water-soluble surfactant is deposited on a bare oil-water interface, flows are induced in water and in oil (Marangoni effect). An investigation shows that the interface is also deformed, with an upward water bump into the oil, and that the vertical shape of the interface is linked to the in-plane surface tension profile.