Abstract

Emerging microscopic imaging tools, including techniques such as confocal and total internal reflectance, provide unprecedented high-resolution, real-time, three-dimensional visualizations of colloidal processes. In some cases, the experimental data approach the level of detail previously found only in particle-based computer simulations. We describe several ways in which we couple the theoretical tools of statistical thermodynamics with the digital optical microscopy techniques of our collaborator, Prof. Michael A. Bevan of Johns Hopkins University, and discuss how the combination may advance both fields. First we show how classical density functional theory (DFT) can be used in an inverse mode to enable a rapid mapping of the potential energy of a surface, using an ensemble of colloidal particles as probes. We also discuss some advances in the use of DFT to predict freezing transitions in systems interacting with colloidal potentials. Finally, we show how experimental data on the time evolution of colloidal trajectories may be used to build free energy landscapes via a Fokker-Planck formalism; such landscapes will be useful in modeling and controlling the directed assembly of colloids into defect-free target structures like photonic crystals.

Biography

David M. Ford is currently an Associate Professor of Chemical Engineering at the University of Massachusetts Amherst. He earned a B.S. degree from the University at Buffalo (State University of New York) and M.S.E. and Ph.D. degrees from the University of Pennsylvania, all in Chemical Engineering. At Penn his thesis advisor was Eduardo D. Glandt. Dr. Ford was a postdoctoral researcher at Sandia National Laboratories with Grant S. Heffelfinger before starting as a faculty member in the Department of Chemical Engineering at Texas A&M in 1997. He was promoted to Associate Professor and holder of the Kenneth R. Hall Professorship in 2003 and remained in that position until he moved to UMass-Amherst in 2006. Dr. Ford received the Department of Energy Defense Programs Early Career Scientist and Engineer Award and the Presidential Early Career Awards for Scientists and Engineers (PECASE) in 1999. He was also an invited participant in the Frontiers of Engineering Symposium of the National Academy of Engineering in 2004.