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An ouzo droplet is a multicomponent liquid comprising ethanol, water, and anise oil, each possessing distinct thermophysical properties, volatility, and mutual miscibility. Evaporation leads to the complex physicochemical process of coupled mass and heat transfer, spontaneous emulsification, and liquid–liquid phase separation, known as the ouzo effect. An acoustically levitated ouzo droplet undergoes five characteristic stages of evaporation based on temporal temperature variation. Such levitated droplet shows a significantly longer lifespan upon evaporation because of the thermal isolation in air, as well as a drastic initial cooling. Sessile droplets, on the other hand, have heat transferred from the surroundings via the substrate to replenish latent heat of vaporization. A conductive substrate thus helps the droplet to stay close to the ambience and a shorter lifespan. A rudimentary theoretical model based on dimensional analysis is developed and shows consistency with measurements. [ABSTRACT FROM AUTHOR]

A levitated glycerol droplet supported by an acoustic standing wave, when subject to modulated field at frequency on the order of 150 Hz, behaves as a solid plate and exhibits flexural bending resonance rather than the conventional equatorial star-shape oscillations. Three oscillation modes are observed: seesaw, saddleback, and monkey saddle with the increasing energy levels. The finite element analysis generates droplet shapes consistent with the experimental observation and yields apparent plate flexural rigidity in terms of surface tension and aspect ratio of plate thickness to diameter. High viscosity leads to the plate-like behavior of the droplet. [ABSTRACT FROM AUTHOR]