Harvard University

报告人简介：
Professor David A. Weitz, member of National Academy of Sciences (USA) and American Academy of Arts and Sciences, is a Canadian/American physicist and Mallinckrodt Professor of Physics & Applied Physics and professor of Systems Biology at Harvard University. He is the co-director of the BASF Advanced Research Initiative at Harvard, co-director of the Harvard Kavli Institute for Bionano Science & Technology, and director of the Harvard Materials Research Science & Engineering Center. Professor Weitz received his PhD in superconductivity from Harvard in 1978. He then worked as a research physicist at Exxon Research and Engineering for nearly 18 years, leading the Interfaces and Inhomogeneous Materials Group and Complex Fluids Area. He then became a Professor of Physics at the University of Pennsylvania, before moving to Harvard in 1999.

报告摘要:
This talk will describe new results on model colloid systems that provide insight into the behavior of fundamental problems in colloid physics, and, more generally, for other materials as well. By visualizing the nucleation and growth of colloid crystals, we find that the incipient crystallites are much more disordered than expected, leading to a larger diversity of crystal morphologies. When the entropic contribution of these diverse morphologies is included in the free energy, we are able to describe the behavior very well, and are able to predict the nucleation rate surprisingly accurately. The talk will also describe the glass transition in deformable colloidal particles, and will show that when the internal elasticity of the particles is included, the colloidal glass transition mimics that of molecular glass formers much more completely. These results also suggest that the elasticity at the scale of the fundamental unit, either colloid particle or molecule, determines the nature of the glass transition, as described by the 'fragility'.

联 系 人：叶方富（82649779）