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)来研究薄液层和相关的新型液体表面的结构性质。在不同衬底上形成的薄液体润湿层的结构和波动将由X射线镜面反射率、偏离镜面漫反射和掠入射衍射来表征。一个独特的特征是，一些润湿将涉及一种液体被另一种不相容的液体润湿。选择的纳米粒子在这些薄层中的溶剂化，伴随着液体厚度的控制，将使研究二维(2D)介观阵列如何从溶液沉积形成成为可能。此外，还将研究稀薄的润湿液体与硅表面纳米结构之间的相互作用，以及随着纳米颗粒密度的变化，烷烃链与纳米颗粒有序连接的方式。除了预期的科学知识外，该项目预计将带来的第二个好处是，新的年轻研究人员将接受培训，利用这些宝贵的国家同步加速器设施进行尖端研究。此外，参与这笔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(例如，http://www.mrsec.harvard.edu/education.html)教师研究体验计划，该计划使当地K-12学校的教师能够参与研究。了解液体表面和薄液体薄膜的结构和相关物理性质对于包括润滑、粘合、催化、涂装和涂层在内的各种过程非常重要。此外，润湿现象的实验和理论研究对当前理解统计物理中的基本问题做出了重要贡献。例如，研究具有纳米级不均匀的衬底的润湿对于开发一种技术上有前途的微印刷方法来生产纳米级结构具有重要意义。

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.