Levich Institute Seminar Announcement, 02/28/2017
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor James Swan
Massachusetts Institute of Technology
Department of Chemical Engineering
"The Hydrodynamics of Colloidal Gelation"
Colloidal gels are formed during arrested phase separation. Sub-micron, mutually attractive particles aggregate to form a system-spanning network with high interfacial area, far from equilibrium. Models for microstructural evolution during colloidal gelation have often struggled to match experimental results with long standing questions regarding the role of hydrodynamic interactions. In the present work, we demonstrate simulations of gelation with and without hydrodynamic interactions between the suspended particles. The disparities between these simulations are striking and mirror the experimental-theoretical mismatch in the literature. The hydrodynamic simulations agree with experimental observations, however. We explore a simple model of the competing transport processes in gelation that anticipates these disparities, and conclude that hydrodynamic forces are essential. We show through detailed simulations and analytical theory how competing transport processes are affected by hydrodynamic interactions between colloids and extend the simulations beyond the quasi-static limit to study the breakdown of gels under flow. Our simple model is capable of reproducing the results from a variety of flow scattering experiments, and suggest a pathway to understanding the co-evolution of structure and stress in flowing, attractive dispersions.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
Dr. James W. Swan is an assistant professor in the Department of Chemical Engineering at MIT. Dr. Swan received a BS in Chemical Engineering in 2004 from the University of Arizona and a Ph. D. in 2010 in Chemical Engineering from the California Institute of Technology. From 2011-2013, he was a postdoctoral scholar in the Department of Chemical and Biomolecular Engineering at the University of Delaware. He is the recipient of an NSF Career Award and a new investigator award from the ACS Petroleum Research Fund.
RECENT RESEARCH INTERESTS
Dr. Swan currently focuses on how nano-particle dispersions can be self-assembled to produce materials with prescribed mechanical and transport properties. His research on soft matter is broad and has included modeling of confined colloidal dispersion, accurate measurement of biophysical forces and the self-assembly nano-particles in microgravity. Now, Dr. Swan aims to combine theory and simulation to facilitate modeling of fluid mechanics and out-of-equilibrium statistical physics that are fundamental to complex fluids and other soft matter.