Role of convective evaporation on thin film lifetime

Surface bubbles play a key role in the coupling between ocean and atmosphere dynamics. In particular, these bubbles generate sea-salt aerosols, which in turn influence processes in the atmosphere such as radiative balance and cloud formation. The aerosols are formed when a bubble bursts in an ensemble of droplets containing salt and other contaminants from the ocean surface. Some open questions remain on the mechanisms behind the production of salt aerosols, for which the most observed size is around 100 nm regardless of the salt concentration. We investigate how the addition of salt modifies thin liquid film dynamics, from drainage to bursting. We perform an idealized experiment consisting of a salted flat soap film supported by a vertical frame. This setup allows us to directly probe the evolution of the thickness of the thin liquid film and thus visualize the effect of the salt on different draining mechanisms. We measure the lifetime and thickness of such films as a function of humidity and salt concentration. The effect of humidity on lifetime shows a striking contrast depending on whether the air in the chamber is agitated or not. To properly assess the lifetime of those thin films in situations resembling oceanic conditions, we show that the atmosphere around the film should be continuously mixed.