(168aa) Effect of Low-Reynolds Number Flow On Surfactant Transport to a Stationary Spherical Cap: Experiments and Theory

Using a newly developed tool, denoted a microtensiometer, surfactant transport to microscopic interfaces is measured by simultaneously measuring the pressure jump across the interface and the radius of the interface. Using this apparatus, we impose low-Reynolds number flow parallel to the capillary at which a spherical fluid-fluid interface is pinned (i.e. as in co-flow). The surfactant is dissolved in the liquid outside of the bubble/drop interface. We examine the role of the co-flow on the dynamics of surfactant transport to the interface and interpret these results in the context of an advection-diffusion model of soluble amphiphiles undergoing a co-flow parallel to the interface.