Structure of Liquid Surfaces

该项目主要利用布鲁克海文国家实验室的国家同步加速器光源（NSLS）和阿贡国家实验室的先进光子光源（APS）对同步加速器产生的x射线散射进行研究，以研究薄液体层和相关新型液体表面的结构特性。用x射线镜面反射率、非镜面漫射散射和掠入射衍射来表征在各种衬底上形成的薄液体润湿层的结构和波动。一个独特的特点是，一些润湿将涉及到一种液体被另一种不混相液体润湿。将选定的纳米颗粒溶解在这些薄层中，同时控制液体的厚度，将使研究如何在溶液沉积中形成二维介观阵列成为可能。此外，还将研究硅表面上的薄润湿液体与纳米级结构之间的相互作用，以及随着纳米颗粒密度的变化，烷烃链与纳米颗粒的连接顺序。除了预期的科学知识之外，这个项目的第二个好处是，新的年轻研究人员将得到培训，利用这些宝贵的国家同步加速器设施进行尖端研究。此外，参与这项资助的研究人员将参与哈佛大学正在进行的教育推广活动（见http://www.mrsec.harvard.edu/education.html），例如，教师研究经验计划（RET），该计划使当地K-12学校的教师有可能参与研究。了解液体表面和液体薄膜的结构和相关物理性质对于包括润滑、粘附、催化、油漆和涂层在内的各种工艺都很重要。此外，润湿现象的实验和理论研究对当前对统计物理基本问题的理解做出了重大贡献。例如，研究具有纳米尺度不均匀性的衬底的润湿对于开发用于生产纳米尺度结构的技术上有前途的微印刷方法非常重要。

This project focuses on synchrotron generated x-ray scattering using the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory and the Advanced Photon Light Source (APS) at Argonne National Laboratory to study the structural properties of thin liquid layers and related novel liquid surfaces. The structure and fluctuations of a thin liquid wetting layer that forms on various substrates will be characterized by x-ray specular reflectivity, off specular diffuse scattering and grazing incidence diffraction. A unique feature is that some of the wetting will involve the wetting of one liquid by a separate immiscible liquid. Solvation of selected nano-particles in these thin layers, accompanied by control of the thickness of the liquid, will make it possible to the study how 2-dimensional (2D) mesoscopic arrays form on deposition from solution. In addition, the interactions between thin wetting liquids and nano-scale structures on Si surfaces, and the manner in which alkane chains tethered to nano-particles order as the density of the nano-particles change will be investigated. A second benefit expected from this project, in addition to the expected scientific knowledge, is that new young researchers will be trained to carry out cutting edge research using these precious national synchrotron facilities. In addition, researchers participating in this grant will participate in the ongoing educational outreach activities at Harvard (see http://www.mrsec.harvard.edu/education.html) for example, the Research Experiences for Teachers program (RET) that makes it possible for teachers from local-area K-12 schools to participate in research.Understanding the structure and related physical properties of liquid surfaces and thin liquid films are important for a variety of processes that include lubrication, adhesion, catalysis, painting, and coatings. In addition, the experimental and theoretical study of wetting phenomena is contributing significantly to the current understanding of fundamental problems in statistical physics. For example, studying the wetting of substrates with nano-scale inhomogeneities is important for developing a technologically promising microprinting method for the production of nano-scale structures.