Stationary hydrodynamics of Marangoni driven spreading of liquids at air-water interfaces by Mahesh Bandi
Host: Prof. Lisa Manning/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45pm
A drop of liquid with lower surface tension than water will spread radially outwards when introduced at an air-water interface, to minimise the interfacial energy. If the liquid drop is insoluble in water (e.g. oil), the transient spreading halts once the liquid covers the surface; a phenomenon with rich theory supported by satisfactory experimental evidence. However if a mechanism exists whereby the spreading liquid can leave the interface (e.g. via dissolution or evaporation), a stationary flux is achieved — the liquid entering the interface (influx) spreads radially over some distance before steady-state flux balance is attained as it leaves the interface (outflux). Not much is known about such processes despite their relatively common occurrence in nature. Although soluble, such surfactants can spread through a phase adsorbed to the interface, requiring a distinction between two clearly different spreading possibilities. In this talk, I will explain our theoretical and experimental investigations to understand these processes. Scaling analysis helps discriminate between the spreading mechanisms, which we verify with experiments.