Levich Institute Seminar Announcement, 10/08/2013
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor Michael Solomon
University of Michigan
Department of Chemical Engineering
"Reconfigurable Colloidal Assembly by Induced Electric Fields"
Assemblies of colloidal particles are common both in nature and in advanced materials - they are one cornerstone of broad efforts to produce reconfigurable soft matter. Assembled arrays of particles can be either static or dynamically produced, and the latter case introduces possibilities to reconfigure assemblies in space and time so they can perform advanced functions such as switching and actuation. Here we show how controlled, programmed application of electric fields can improve prospects for spatial and temporal control of colloidal assemblies. These fields assist assembly by accelerating kinetics and by, potentially, opening up new regions of the assembly phase diagrams of colloidal particles. We focus on three cases. First, direct current electric fields are used to assemble ellipsoidal colloidal rods into new phases with high density. The electrochemical mechanism for the self-assembly is established, and this understanding is used to produce switchable colloidal crystals, an effect that can be modeled by means of colloidal transport phenomena. Second, we show how the induced electric field mechanism can be spatially controlled, so as to produce colloidal assemblies of finite size. Third, we discuss the scope for applying these methods to other kinds of anisotropic colloids, such as Janus particles.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
Mike Solomon is Professor of Chemical Engineering at the University of Michigan. He received his Ph.D. at the University of California at Berkeley in 1996. After a post-doctoral appointment at the University of Melbourne, Australia, he joined the faculty at the University of Michigan. He received Michigan Engineering's Education Excellence Award in 2010 and was the recipient of the 2011 Soft Matter Lectureship, awarded by The Royal Society of Chemistry's journal Soft Matter. He is currently Associate Dean of Academic Programs and Initiatives in the Rackham Graduate School at the University of Michigan
RECENT RESEARCH INTERESTS
Colloidal assembly, gel rheology, and the biomechanics of bacterial biofilms