Spreading Bubbles:
While the dynamics of wetting has been widely studied for a liquid on a solid, the situation where air and water are exchanged is less known. We report here the events following the rise of a millimeter-size air bubble towards a superhydrophobic obstacle immersed in water. Once contact is established, the bubble will spontaneously spread on the solid. Our aim is to describe the dynamics of this inertial spreading. At very short times, a Culick regime is observed, quickly followed by capillary expansion of the spherical cap of air. Once the radius is in the range of the capillary length, we observe an inflexion in the spreading dynamics due to buoyancy, which tends to flatten further the bubble. Spreading typically occurs within 10ms.
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