Manipulating Soft Materials with Interfacial Dynamics: From Bubble Bursting to Nanoparticle Denaturation
September 19, 2019
11:00 AM - 12:00 PM
Manipulating Soft Materials with Interfacial Dynamics: From Bubble Bursting to Nanoparticle Denaturation
Presenter: Jie Feng, Assistant Professor of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Champaign
Abstract: Interfaces between two distinct phases are ubiquitous in nature and many engineering processes. From the fundamental studies in physics, materials and biology, to applications in various fields, interfaces control many aspects of the thermodynamics and dynamics of multi-phase systems. Not surprisingly, questions about the dynamics of interfaces, e.g., their flow and response to forces, occur widely in colloid science, fluid mechanics and other areas of science and engineering. Therefore, understanding various interfacial dynamics remains a canonical problem with strong intellectual interest and broad industrial impacts.
In this talk, we will describe two distinct problems where we investigate the interfacial dynamics of structured complex fluids, and the understandings can be extended to soft materials engineering for applications in the environmental and health science. First, we will present the study of bubble bursting at a compound air-oil-water interface. We document the hitherto unreported formation and dispersal of submicrometer oil droplets into the water column. Surprisingly, the droplet size is selected by the physicochemical interactions rather than by hydrodynamic effects. The implications of the dispersal mechanism for oil-spill remediation and multi-functional nanoemulsion formation will also be demonstrated. Second, we will discuss the evolution of polymeric nanoparticle attachment at an air-liquid interface over time scales from 100 millisecond to a few seconds. We document three distinct stages in the nanoparticle adsorption. In addition to an early stage of free diffusion and a later one with steric adsorption barriers, we find a hitherto unrealized region where the interfacial energy changes due to surface “denaturation” or restructuring of the nanoparticles at the interface. We adopt a quantitative model to calculate the diffusion coefficient, adsorption rate and barrier, and extent of nanoparticle hydrophobic core exposure at different stages. Our findings offer new insights for the interfacial behavior of nanoparticles, as well as the application of their controlled release at the interface.
Presenter bio: Jie Feng is an assistant professor in the Department of Mechanical Science and Engineering at the University of Illinois at Urbana-Champaign. He obtained his PhD in mechanical and aerospace engineering from Princeton University and did his postdoctoral research in chemical and biological engineering at Princeton University before joining the University of Illinois in January 2019. The research interests of his group lie in understanding the fundamental interfacial transport phenomena in structured complex fluids at a microscopic scale, to derive new insights for innovative materials engineering platforms to provide solutions to some of today’s most challenging problems in the environment remediation and human health. Currently, the research thrusts include bubble and vesicle dynamics at complex spaces, multi-phase dynamics related to thin-film flows, polymer self-assembly for structured nanoclusters and nanoparticle-oriented engineering for diagnostic delivery and controlled release, He received the Gordon Wu Prize for Excellence and Wallace Memorial Honorific Fellowship for exceptional promise in research from Princeton University in 2016. His research has led to over 20 publications in major scientific journals, such as Nature Physics, Advanced Materials, Nano Letters, Journal of Fluid Mechanics, Soft Matter, Molecular Pharmaceutics, Langmuir and Physical Review Applied.
Date posted
Sep 17, 2019
Date updated
Oct 1, 2019