Dynamics of Selective Adsorption

小行星9802476 在这项研究计划中，教授H。Taub和K.W.位于哥伦比亚的密苏里州大学物理和天文系的赫维格将研究流体混合物中的一种化学成分优先吸附在固体表面的过程。 这种过程在材料科学中广泛存在。 一个特别感兴趣的情况是从溶液中的长柔性链分子的优先吸附，这是一个过程，这是重要的应用，如润滑，粘合和涂层。 尽管在这方面已经取得了相当大的进展， 在理解结构、热力学和宏观时间尺度上的界面附近的这种聚合物的动力学时，对这些系统在原子水平上的动力学知之甚少。 用最简单的术语来说，要解决的问题是聚合物链如何移动以便从固体表面锚、扩散并最终解吸。 在石墨和Ag（111）衬底上的中等大小（含有20至40个碳原子）的直链和支链烷烃分子将被用作原型 系统的动力学研究 选择性吸附准弹性中子散射将用于研究烷烃膜内的扩散运动，而它们的结构将通过中子和同步加速器X射线散射进行研究。 详细的计算机模拟将有助于解释实验。 实验将利用密苏里州大学研究反应堆现有的最先进设施以及阿贡国家实验室的强脉冲中子源和先进光子源。 在这个研究项目中，H. Taub和K.W.位于哥伦比亚的密苏里州大学物理和天文系的赫维格将研究流体混合物中的一种化学成分优先吸附在固体表面的过程。 这种过程在材料科学中广泛存在。 一个特别感兴趣的情况是从溶液中的长柔性链分子的优先吸附，这是一个过程，这是重要的应用，如润滑，粘合和涂层。 不幸的是，在微观水平上，人们对这种聚合物分子如何锚在固体表面上，然后爬行，最终解吸的动力学知之甚少。 在这个项目中， 烃链分子（直链和支链烷烃）是商业润滑剂的主要成分，将用作研究选择性吸附动力学的原型。 准弹性中子散射将被用来研究碳氢化合物膜内的分子运动，而它们的结构将被中子和同步加速器X射线散射研究。 详细的计算机模拟将有助于解释实验。实验将利用密苏里州大学研究反应堆现有的最先进设施以及阿贡国家实验室的强脉冲中子源和先进光子源。 这项研究将为研究生提供聚合物科学基础方面的培训，为他们在石油和橡胶行业的职业生涯做好准备。 ***

9802476 Taub In this research program, Professors H. Taub and K.W. Herwig of the Department of Physics and Astronomy of the University of Missouri at Columbia will investigate processes in which one chemical component in a fluid mixture preferentially adsorbs on a solid surface. Such processes occur widely in materials science. A case of particular interest is the preferential adsorption from solution of long flexible-chain molecules, a process which is important in such applications as lubrication, adhesion, and coatings. Whereas considerable progress has been made in understanding the structure, thermodynamics, and, on macroscopic time scales, the kinetics of such polymers near interfaces, little is known of the dynamics of these systems at the atomic level. In simplest terms, the questions to be addressed are how do polymer chains move so as to anchor, diffuse, and eventually desorb from a solid surface. Both linear and branched alkane molecules of intermediate size (containing between 20 and 40 carbon atoms) on graphite and Ag(111) substrates will be used as prototype systems for studying the dynamics of selective adsorption. Quasielastic neutron scattering will be used to study the diffusive motion within the alkane films, while their structure will be investigated by neutron and synchrotron x-ray scattering. The interpretation of the experiments will be assisted by detailed computer simulations. Experiments will utilize existing state-of-the-art facilities at the Missouri University Research Reactor and both the Intense Pulsed Neutron Source and Advanced Photon Source at Argonne National Laboratory. %%% In this research program, Professors H. Taub and K.W. Herwig of the Department of Physics and Astronomy of the University of Missouri at Columbia will investigate processes in which one chemical component in a f luid mixture preferentially adsorbs on a solid surface. Such processes occur widely in materials science. A case of particular interest is the preferential adsorption from solution of long flexible-chain molecules, a process which is important in such applications as lubrication, adhesion, and coatings. Unfortunately very little is known at the microscopic level about the dynamics of how such polymer molecules anchor to a solid surface, then crawl about, and eventually desorb. In this project intermediate-length hydrocarbon-chain molecules (both linear and branched alkanes), which are the principal constituents of commercial lubricants, will be used as prototypes for studying the dynamics of selective adsorption. Quasielastic neutron scattering will be used to investigate the molecular motion within the hydrocarbon films, while their structure will be investigated by neutron and synchrotron x-ray scattering. The interpretation of the experiments will be assisted by detailed computer simulations. Experiments will utilize existing state-of- the-art facilities at the Missouri University Research Reactor and both the Intense Pulsed Neutron Source and Advanced Photon Source at Argonne National Laboratory. This research will provide training of graduate students in fundamental aspects of polymer science, preparing them for careers in the petroleum and rubber industries. ***