Levitation of fizzy fluids

Liquids generally spread on solids they encounter. However, under particular circumstances, such a wetting can be reduced or even avoided, a situation of obvious practical interest in terms of anti-adhesion or even thermal and mechanical insulations. By using superhydrophobic coating, a water drop can thus limit its contact with the substrate at a low fraction. Liquid levitation can even be achieved using the volatility of the liquid and creating a thin insulating vapor layer as early described by Leidenfrost in 1756. More recently, other strategies have been developed involving external fields such as air flows, Faraday waves or magnetic fields. We here describe a novel approach using active liquids able to sustain levitation in the absence of external forces. We will first discuss the levitation of carbonated water. In this regime, the drop self-generates the gas cushion which provides levitation. We will model the lubrication theory behind this insulation. Finally, we will generalize this new regime to different kinds of substrates and non-volatile liquids.