Liquid Surfaces and Interfaces: X-ray Studies

技术摘要液体表面和界面在物理、化学、地质、生物等领域以及各种实际过程和产品中起着至关重要的作用，如润滑、粘合、过滤、采油、润湿/铺展/涂层、气溶胶和乳状液等。长期以来，理论上一直预测，所有液体在其自由表面附近都会有非各向同性的有序(层)，而不是传统的将液体状态视为各向同性的连续体。近年来，由于美国国家科学基金会资助的这一小组的研究，已经确定非金属液体在足够低的温度下确实会产生表面有序。这些表面的结构和机械性能将使用X射线反射率、非镜面散射和X射线光子相关光谱进行详细表征。将寻求这些液体在其自由表面的有序性和它们在液-固界面上的有序性之间的关系，以试图了解这些关系是否可以在一个共同的框架内解释。将寻求确定普遍的定性和定量特征和趋势，以帮助制定更先进的理论图景。该项目将通过在跨学科环境中培养研究生来整合研究和教学。与液体有关的主题将被纳入本科生和研究生课程以及网络传播的教材。研究结果将通过传统的科学渠道和网页提供。非技术摘要液体表面和界面在物理、化学、地质、生物等方面以及在许多现实世界的过程和产品中起着至关重要的作用，如润滑、粘合、过滤、石油回收、润湿/铺展/涂层、气雾剂和乳状液等。由于最近的进展，人们现在知道液体中的原子或分子可以在表面附近排列成层。因此，纳米尺度的表面区类似于液晶，而不是液体本身。该项目的目标是利用同步辐射对这一现象进行详细和系统的研究。从这些研究中获得的知识可能不仅有助于确定液体表面性质与整体液体性质的不同之处，而且还有助于确定为什么。因此，这些研究最终可能会因为能够更好地控制表面发生的过程而给社会带来好处。该项目将通过在跨学科环境中培养研究生来整合研究和教学。与液体有关的主题将被纳入本科生和研究生课程以及网络传播的教材。研究结果将通过传统的科学渠道和网页提供。

Technical abstractLiquid surfaces and interfaces play crucial roles in physics, chemistry, geology, biology, etc., and in a large variety of real-world processes and products such as lubrication, adhesion, filtration, oil recovery, wetting/spreading/coating, aerosols and emulsions, etc. It has long been theoretically predicted that all liquids will have non-isotropic order (layers) near their free surfaces, in contrast to the conventional view of the liquid state as an isotropic continuum. In recent years, as a result of NSF-supported research in this group, it has been established that nonmetallic liquids do develop surface order at sufficiently low temperatures. The structural and mechanical properties of these surfaces will be characterized in detail using X-ray reflectivity, off-specular scattering, and X-ray photon correlation spectroscopy. Relationships will be sought between the ordering of these liquids at their free surfaces and their ordering at liquid-solid interfaces, to try to learn whether these can be explained within a common framework. Identification of universal qualitative and quantitative features and trends will be sought in order to help the development of a more advanced theoretical picture. This project will integrate research and teaching by training graduate students in an interdisciplinary environment. Liquids-related topics will be incorporated into undergraduate and graduate courses and web-disseminated teaching materials. The results of the research will be made available through traditional scientific channels and also through web pages. Nontechnical abstractLiquid surfaces and interfaces play crucial roles in physics, chemistry, geology, biology, etc., and in a large variety of real-world processes and products such as lubrication, adhesion, filtration, oil recovery, wetting/spreading/coating, aerosols and emulsions, etc. As a result of recent advances, it is now known that the atoms or molecules in liquids can arrange themselves into layers near the surface. The nanoscale surface region thus resembles a liquid crystal rather than the liquid itself. The objective of this project is a detailed and systematic study of this phenomenon using synchrotron radiation. The knowledge gained from these studies may help determine not only how liquid surface properties are different from bulk liquid properties, but why. Therefore, these studies may ultimately lead to benefits to society from being able to better control processes occurring at surfaces. This project will integrate research and teaching by training graduate students in an interdisciplinary environment. Liquids-related topics will be incorporated into undergraduate and graduate courses and web-disseminated teaching materials. The results of the research will be made available through traditional scientific channels and also through web pages.