Dynamic Probes of Tribological Processes

迪金森这些研究集中在纳米级表面处理的基本机制和应用，涉及复合刺激，其中扫描力显微镜的尖端在具有侵略性的化学溶液存在的情况下刺激表面。这些组合的刺激可以在单晶、玻璃和聚合物的表面以高度局域的方式建立和断开键并重组材料。我们将研究晶体和其他结构缺陷(例如，由针尖产生的台阶、扭结、空位和纳米结构)在溶解和生长中的作用，以确定限速步骤(在有和没有SFM针尖的刺激下)以及它们如何依赖于应力、溶液化学和温度。这些结果将与控制溶解和生长的基本物理和化学参数有关，例如活化能和体积/熵因子。我们还将研究扫描过程中悬臂梁表面的随机机械振动如何与过饱和溶液中的瞬时表面现象有关。这些研究在开发产生原子平坦表面的新方法、构建新的纳米结构、以及产生用于粘合和化学活性排列的纹理表面方面具有相当大的前景。这些研究还支持对化学机械抛光(CMP)这一技术上重要的过程的原子水平的理解，在该过程中，SFM尖端用作模型磨料颗粒。传感器开发、MEMS以及新的生物活性底物和表面的开发将受益于这项工作在分子水平上对溶解和生长的更好理解。***

0116169DickinsonThese studies focus on fundamental mechanisms and applications of nanometer scale surface manipulation involving combined stimuli, where the tip of a scanning force microscope stimulates the surface in the presence of an aggressive chemical solution. These combined stimuli can make and break bonds and reorganize material on surfaces of single crystals, glasses, and polymers in a highly localized fashion. We will examine the role of crystalline and other structural defects (e.g., steps, kinks, vacancies, and nanostructures generated by the tip) in dissolution and growth to identify the rate limiting steps (with and without stimulation by the SFM tip) and how they depend on stress, solution chemistry, and temperature. These results will be related to fundamental physical and chemical parameters governing dissolution and growth, such as activation energies and volume/entropic factors. We also will examine how the apparently random mechanical vibrations in cantilevers during scanning might be related to transient surface phenomena in supersaturated solutions. These studies have considerable promise in the development of new methods for generating atomically flat surfaces, constructing novel nanometer structures, and producing textured surfaces for bonding and chemically active arrangements. The studies also support atomic level understanding of the technologically important process of chemical mechanical polishing (CMP), where the SFM tip serves as a model abrasive particle. Sensor development, MEMS, and development of new biologically active substrates and surfaces will benefit from the improved molecular-level understanding of dissolution and growth resulting from this work. ***