Interface breakthrough and sphere coating

The passage of a sphere through a liquid-liquid interface is studied experi mentally in the particular case of a highly viscous upper liquid. For low v alues of the modified Bond number beta the motion of the sphere consists of two distinct regimes: a slow draining stage of the upper liquid film trapp ed between the sphere and the interface, and a rapid one where a liquid tai l bridges the sphere to the upper phase. It is found that the volume of liq uid carried away by the sphere varies as ln beta and that the time necessar y for breakthrough varies as 1/ln beta. (C) Academie des sciences/Elsevier, Paris.