Collision between an ethanol drop and a water drop

The collision between a water drop and an ethanol drop was studied. In a binary collision between unlike miscible drops with a large surface tension difference, an "unbalanced-surface-force" (USF) deformation on the drop of larger surface tension, i.e., the water drop, occurs during the first stage of the collision. This deformation may squeeze out small satellites from the water drop at low-impact-parameter collisions or split the water drop at high-impact-parameter collisions. The later stages of the collision behavior, namely, coalescence and separation, resemble those of the drops of the smaller surface tension, i.e., the ethanol drop.