Interface breakthrough and sphere coating

The passage of a sphere through a liquid-liquid interface is studied experimentally in the particular case of a highly viscous upper liquid. For low values 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 trapped between the sphere and the interface, and a rapid one where a liquid tail bridges the sphere to the upper phase. It is found that the volume of liquid carried away by the sphere varies as ln beta and that the time necessary for breakthrough varies as 1/ln beta. (C) Academie des sciences/Elsevier, Paris.