Lynn WalkerDepartment of Chemical Engineering, Carnegie Mellon University, Pittsburgh PA
Systems involving deformable interfaces between immiscible fluids offer a significant challenge for materials design and processing. Static interfacial/surface tension is often the only parameter considered in the design of systems with fluid-fluid interfaces. In foams, emulsions, blends, sprays, droplet-based microfluidic devices and many other applications, the dynamic nature of surface active species and deformation of interfaces requires a more detailed characterization of the interfacial transport, dynamic interfacial properties and interfacial structure. Macroscopic properties and the ability to tune and control phenomena requires an improved understanding of the time-dependent properties of the interfacial tension and interfacial mechanics. We have developed tools and approaches to quantify the impact of surface active species on interfacial behavior. Simple surfactants at interfaces make evident the need to characterize timescales in the adsorption problem. Polymer-grafted nanoparticles, polymer-surfactant aggregates and proteins show the ability to bridge between macromolecular and particulate (Pickering) laden interfaces. This talk will provide the motivation to use microscale interfaces for efficient analysis of complex interfacial phenomena and how that relates to the material properties of interface-dominated materials.
Bio Lynn M. Walker is a Professor of Chemical Engineering and both Chemistry (by courtesy) and Materials Science & Engineering (by courtesy) at Carnegie Mellon University. She holds a B.S. degree from the University of New Hampshire and a Ph.D. from the University of Delaware, both in chemical engineering. She was an NSF International Postdoctoral Fellow at the Katholieke Universiteit in Leuven, Belgium before joining Carnegie Mellon University in 1997. She spent 2007 as a visiting professor at the Polymer IRC at the University of Leeds in the United Kingdom. Her research focuses on quantifying the coupling between flow behavior and flow-induced microstructure in complex fluids. Current research focuses in two directions; quantifying the influence of flow on self-assembled nanostructures and controlling transport to complex fluid-fluid interfaces. She is the recipient of the DuPont Young Faculty Research Grant and an NSF CAREER award. She has twice been recognized for teaching by receiving the Kun Li Award for Excellence in Education from the Department of Chemical Engineering at Carnegie Mellon University, is the 2016 recipient of the Lazarus Award for Mentoring from CMU and the 2015 WIC Mentorship Excellence Award from AIChE. She is the Editor-in-Chief of Rheologica Acta and serves on the editorial boards of the Journal of Rheology and Industrial & Engineering Chemistry Research. She is a member of the E&PS technical advisory board at Dow Chemical, as well as serving on committees for AIChE and the Society of Rheology.
Host: Vivek Sharma