The Life of a Thermal Marangoni Bubble

Air injected in a pool of pure liquid forms bubbles at the interface that do not live long, unlike bubbles that dwell on a bath containing surfactants. Here we consider a situation where the pool is pure (made of oil), yet hot. We find that the bubbles at the surface can then live for minutes or even longer. We interpret this longevity as a consequence of the gradients of temperature generated in this experiment - oil is observed to be continually drawn to the apex of the bubble opposing its gravitational drainage, which reveals the dynamical nature of the lives of the thermal bubbles. A little bit of heat not only breaks the ephemerality of bubbles of pure liquids, but also endows the oil film with a remarkable stability and persistence.