Relaxation Dynamics in Glassy Systems and Pattern Formation

点击翻译按钮获取中文摘要

9722646 Nagel This renewal project contains a series of experiments concerning the dynamics in supercooled liquids. In particular, an extension of dielectric spectroscopy will be implemented so that an investigation of "strong" glass formers can be made possible. A study of ordered materials will be carried out to see if they have the same complex response as has been observed in their disordered counterparts. Finally, there will be a study of the low-angle scattering from glass-forming liquids in order to search for clustering effects. In addition, experiments on pattern formation are proposed. There will be a continuation of earlier photographic and simulation studies that probe the interface near where a single drop of liquid splits into two separate pieces. In addition there will be an investigation of the shape of the fluid in the presence of an intense electric field. Finally there will be a study of the problem of contact line sedimentation, a phenomenon which occurs whenever a partially wetting drop of liquid dries on a surface. %%% This renewal project contains a series of experiments concerning the mechanism by which a liquid becomes increasingly more resistant to flow as it is cooled. If cooled sufficiently, it will form a glass where the molecular motion is highly constrained. We will study the molecular motion in a variety of liquids and disordered solids to understand this glass-formation phenomenon. These studies will include electronic probes of the behavior as well as the use of neutron and synchrotron sources. In addition, experiments are proposed to investigate how pattern formation occurs in technologically important situations using high- speed photography and numerical simulations. One situation that will be studied is how a drop of liquid splits into more than one piece. There will also be an investigation of the shape of the fluid in the presence of an intense electr ic field. Finally there will be a study of the problem of contact-line sedimentation, a phenomenon occurring whenever a drop of liquid dries on a surface. ***