Sharon C. Glotzer, PhD, NAS, NAE
Anthony C. Lembke Department Chair of Chemical Engineering,
John W. Cahn Distinguished University Professor of Engineering,
Stuart W. Churchill Collegiate Professor of Chemical Engineering
University of Michigan
On the nature of the entropic bond in colloidal crystals
The ability to predict, design and make the perfect material with just the right properties to do what we want, how we want, and when we want is the holy grail of materials research. Such “materials on demand” require control over thermodynamics, kinetics, nonequilibrium behavior, and structure across many length and time scales. With continuing advances in computer simulation capabilities, we have never been closer to the goal, but many challenges – and opportunities – remain. Many of those are at the boundaries of the subfields of materials research, where ideas from one area spur advances in others, and where computational tools and concepts are transferable across domains and scales. At the same time, foundational understanding at one scale can help understand new discoveries at different scales, regardless of the nature of the material and the forces holding it together. In this lecture, we show how atomic and molecular crystal structures – made possible by chemical bonds – can be realized in silico for non-interacting nanoparticles and colloids via entropic bonds. We show that similar crystallization pathways are followed by both molecular and colloidal fluids regardless of driving forces or relevant length scales. Finally, we show how colloidal crystal prediction may be amenable to modern tools used for atomic crystal prediction.
Sharon C. Glotzer is the John W. Cahn Distinguished University Professor of Engineering and the Stuart W. Churchill Collegiate Professor of Chemical Engineering and Professor of Materials Science and Engineering at the University of Michigan, Ann Arbor, and also holds faculty appointments in Physics, Applied Physics, and Macromolecular Science and Engineering. Since July 2017 she is the Anthony C. Lembke Department Chair of Chemical Engineering at the University of Michigan. Her current research on computational assembly science and engineering aims toward predictive materials design of colloidal and soft matter. Using computation, geometrical concepts, and statistical mechanics, her research group seeks to understand complex behavior emerging from simple rules and forces, and use that knowledge to design new materials. Glotzer’s group also develops and disseminates powerful open-source software including the particle simulation toolkit, HOOMD-blue, which allows for fast molecular simulation of materials on graphics processors, the signac framework for data and workflow management, and several analysis and visualization tools.
Department of Chemical Engineering