Adhesive and Mechanical Behavior of Short Molecules

分子自组装单分子膜是一种高度有序的表面膜，由短的有机分子组成，分子厚度为2-3 nm，就像麦田里的麦秆一样。它们决定着薄膜的结构、机械性能和粘合性能。自组装膜对于各种工程系统都很重要，从粘合剂到微机械润滑剂，再到纳米光刻和纳米结构器件和材料。在所有情况下，必须了解使用SAM的系统的设计的粘合剂，摩擦和机械行为。然而，对这种行为知之甚少，本研究假设自组装膜的力学行为可以从相对简单应力状态的分子分析中获得，并用于纳米压痕中出现的更复杂应力状态的连续分析实验和越来越多的SAM基材料系统和结构。这一假设将被检查为几个不同的SAM和表面使用分子分析的一个更广泛的简单的表征应力状态和时间尺度，和正常的压痕实验加上切向加载使用界面力显微镜probes.The项目将提供广泛的培训学生谁将是生产性的跨学科环境中工作在大学或工业。一名本科生也将被纳入该项目。德克萨斯州的人口统计数据是这样的，在UT-奥斯汀的本科生机构有一个显着的西班牙裔代表（约20%在ASE部门），我们成功地鼓励谁参加我们的本科生推广计划。

Molecular self-assembled monolayers (SAMs) are highly organized surface films, one molecule (2-3 nm) thick, composed of short organic molecules which assemble like stalks of wheat on a wheat field. They govern the structure and mechanical and adhesive behavior of the films. SAMs are important for a wide range of engineered systems, from adhesives to micromachine lubricants to nanolithography and nanostructured devices and materials. In all cases, the adhesive, frictional and mechanical behavior must be understood for the design of systems that make use of SAMs However, very little is known about this behavior, particularly under combined loadings.The hypothesis for this study is that the mechanical behavior of SAMs may be obtained from molecular analyses of relatively simple stress states and used in continuum analyses of more complex stress states that arise in nanoindentation experiments and in the growing array of SAM-based materials systems and structures. This hypothesis will be examined for several different SAMs and surfaces using molecular analyses of a broader range of simple characterizing stress states and time scales, and normal indentation experiments coupled with tangential loading using interfacial force microscope probes.The project will provide broadly trained students who will be productive working in interdisciplinary environments at universities or in industry. One undergraduate student will also be incorporated in the project. Texas demographics are such that the undergraduate body at UT-Austin has a significant Hispanic representation (~20% in the ASE Department), who we successfully encourage to participate in our undergraduate outreach programs.