CAREER: Discovering the Mechanisms of Liquid Phase Epitaxy and Bringing Intermolecular Forces to the Physics Curriculum

职业：发现液相外延机制并将分子间力引入物理课程

• 批准号: 0094385
• 负责人: Srinivas Manne
• 金额: $ 45万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0094385&HistoricalAwards=false
• 关键词: CAREER; Discovering; Mechanisms; Liquid; Phase

Recent breakthroughs in mesoscopic materials have reinvigorated the science of solid-liquid interfaces and shifted its emphasis from bulk thermodynamic descriptions to intermolecular forces. The goals of this project are to establish a central facility for the measurement and mapping of intermolecular and surface forces by atomic force microscopy (AFM) and, through student research, to discover the role of solid surfaces in directing interfacial order formation in an adjoining liquid phase (liquid phase epitaxy). First, the nucleation and overgrowth of a solid phase over a different substrate will be investigated by in-situ imaging in metastable solutions. Studies will focus on differences in growth morphology (wetting vs. island nucleation vs. needle growth) as a function of compatibility between substrate and overlayer. Second, force measurements and soft contact imaging will explore the interfacial self-assembly of surfactant solutions and the templating of lyotropic phases by interfacial micelles. Observed interfacial morphologies will be correlated with theoretical calculations based on optimizing the net interaction energy of the micelle lattice and substrate. The role of temperature in structural phase transitions will be explored using an existing temperature-control cell that operates over the aqueous range of temperatures. The students participating in this research will be trained in a contemporary area of condensed matter physics and will thereby be prepared to enter the scientific/technical workforce.%%%The partial ordering of a liquid film in contact with a solid surface is central to interfacial processes ranging from crystal growth to mesoscopic materials synthesis to boundary layer lubrication. The goals of this project are to uncover the mechanisms of interfacial order formation by the measurement and mapping of intermolecular forces by atomic force microscopy (AFM). This technique uses a sub-microscopic tip or stylus to measure intermolecular forces and to image surfaces at atomic scales by mapping force variations across the surface. Student experimentalists will use force measurements and imaging in liquid environments to investigate the role of solid surfaces in nucleating solid and liquid crystalline phases from solutions. Crystal growth of one mineral on a second, closely matched solid will be imaged in real time and at molecular resolution in supersaturated solutions. Studies will focus on differences in growth morphology versus the degree of mismatch between the atomic structure of substrate and overlayer. The nucleation of liquid crystalline phases of surfactants or detergents by solid surfaces will also be investigated. The observed structures of interfacial layers will be correlated with theoretical calculations, based on optimizing the net interaction energy of the surface and surfactant aggregate layer. The effects of temperature on these phases will be investigated using a special sample cell currently under operation. These results are expected to shed new light on interfacial processes such as detergency and the synthesis of advanced materials by self-assembly. This research will be conducted with students who will be prepared for scientific/technical employment in academia, industry, and government.

介观材料的最新突破使固定液体界面的科学振兴了，并将其重点从体积热力学描述转移到了分子间力。 该项目的目标是建立一个中央设施，用于通过原子力显微镜（AFM）（AFM）和学生研究来测量和映射分子间和表面力，以发现固体表面在指导界面形成在相邻液相（液相相邻）中的作用。首先，将通过亚稳态溶液中的原位成像研究固相的成核和过度生长。 研究将集中于生长形态的差异（润湿与岛成核与针头生长），这是基板和叠加剂之间兼容性的函数。其次，力测量和软接触成像将探索表面活性剂溶液的界面自组装以及界面胶束对溶裂相的模板。 观察到的界面形态将与基于优化胶束晶格和底物的净相互作用能量的理论计算相关。 温度在结构相跃迁中的作用将使用现有的温度范围内的温度范围内的温度控制细胞来探索。 参与这项研究的学生将在当代凝结物理物理学的当代领域进行培训，因此，将准备进入科学/技术劳动力。%%％；与固体表面接触的液体膜的部分订购对于从晶体生长到介质材料到介质材料的合成到边界层润滑的界面是核心过程。 该项目的目标是通过通过原子力显微镜（AFM）对分子间力进行测量和映射来揭示界面秩序形成的机制。 该技术使用亚显微镜尖端或手写笔来测量分子间力并通过绘制表面上的力变化来测量原子尺度的表面。 学生实验人员将在液体环境中使用力测量和成像来研究固体表面在溶液中固体和液晶相核中的作用。 一秒钟，紧密匹配的固体的晶体生长将在过饱和溶液中实时成像和分子分辨率。 研究将重点介绍生长形态的差异与底物原子结构之间的不匹配程度。 还将研究表面活性剂或清洁剂固体表面的液晶阶段的成核。 基于优化表面和表面活性剂骨料层的净相互作用能量，观察到的界面层的结构将与理论计算相关。 温度对这些阶段的影响将使用当前正在运行的特殊样本单元进行研究。 预计这些结果将为界面过程（例如洗涤剂和通过自组装综合的高级材料合成）提供新的启示。 这项研究将与将为学术界，工业和政府的科学/技术就业做好准备的学生进行。