The Dynamics of Droplets and Holes in Thin Surfactant Films

We perform quantitative measurements of the spreading of an insoluble surfactant on a thin layer of glycerin, starting from either a droplet or hole (anti-droplet) configuration. We make direct measurements of both the radial height profile and the spatial distribution of the fluorescently-tagged surfactant during the spreading process. Remarkably, the surfactant dynamics are quite different for the two cases. We compare these experimental results to numerical solutions using lubrication theory for thin films.