Abstract
When a homogeneous liquid is cooled into its miscibility gap, phase separation sets in. In the early stages, liquid drops of the minority phase appear in the liquid matrix of the second phase. Due to supersaturation, even smaller drops of the majority phase form in these liquid drops, and so on, each drop encapsulating another drop. In the absence of gravity, the equilibrium configuration of a drop of two immiscible liquids consists of a liquid core, encapsulated by the second liquid phase. The oscillation spectrum of such a compound drop corresponds to that of two coupled oscillators, one being driven by the surface tension, while the other is due to the interfacial tension between the two immiscible liquids. Therefore the values of both, the surface and the interfacial tension, can be derived from the frequencies of the coupled oscillations. Such a configuration can be approximately realized by electromagnetic levitation, preferably under microgravity conditions. In this paper, the theory relating the frequency spectrum to the surface and interfacial tensions is presented, and a report on performed and planned microgravity experiments is given.
