Frieder Mugele comments in Nature News&Views on a recent very surprising work by Bill Ristenpart, Howard Stone and others. These authors report in a recent paper in Nature about the stunning observation that oppositely charged water drops in ambient oil do not coalesce if their charge exceeds a certain threshold value. The very surprising observation is related to the competition of electrical stresses and capillarity. The relaxation of electrical charges through thin capillary bridges, which was investigated earlier at PCF in great detail, plays a crucial effect in this context.
