Transport on Liquid Surfaces by Marangoni Flows
MIE Department Seminar
September 29, 2015
11:00 AM - 12:00 PM
Transport on Liquid Surfaces by Marangoni Flows
Stephen Garoff, PhD
Department of Physics, Carnegie Mellon University
Abstract: Gradients in surface excess concentration of surfactants adsorbed to a liquid/liquid interface create surface tension gradients that drive Marangoni flows. Such induced flows have been well studied in the literature. In this talk, we will focus on the ability of the flow to transport various components of the system across the interface. Initially, we will discuss the case when a single drop of surfactant solution is placed on the surface as the source of the surfactant driving the Marangoni flow. The solution also contains a non-surface active specie, and the solvent in the drop is miscible with the subphase. Inert particles are pre- deposited on the surface and are transported across the surface by the Marangoni flow. We track the transport of each component of the system with time. Next, we will examine the case where the surfactant and non-surface active specie are delivered via an aerosol onto the liquid surface. Here the transport mechanism is not the spreading of individual aerosol droplets, but rather the surface tension gradients that develop between areas of direct aerosol deposition and areas outside that region. Finally, we will briefly discuss the case where a mixture of dry surfactant crystals and inert particles is deposited on the liquid surface. The particles are transported by the Marangoni flows, but the method of admixing of the particles and surfactant crystals impacts the net transport of the inert particles. These latter two cases have direct application in the development of surfactant enhanced transport of pulmonary drug in patients with obstructive lung diseases.
Bio: Stephen Garoff is currently a Professor and Department Head in the Department of Physics at Carnegie Mellon University. He also holds a courtesy Professor appointment in the Department of Chemical Engineering and Material Science. His primary areas of research focus on wetting and spreading of fluids on simple and heterogeneous surfaces, interfacial structure of simple and complex fluids, electrophoresis of complex particles, microscopic origins of friction, and pulmonary aerosol drug delivery. He graduated with his PhD in Applied Physics from Harvard University in 1977. Since receiving his degree, Dr. Garoff has worked both in the academia and industry. He is the co-founder of the Pittsburgh Public School/Carnegie Mellon Outreach Program for Mentoring in Science, and has continued his work in outreach and recruitment. He has served on multiple NSF review panels regarding proposals for numerous topics ranging from the liquid-solid interface and its role in ceramic processing to organic thin films. He is also involved in organizing and chairing technical sessions on topics in the ACS, NSF, DEMS, and APS conferences.
Date posted
Oct 14, 2021
Date updated
Oct 14, 2021