Studies of Friction and Adhesion in Nanoscale Asperity-Asperity Contacts

诸如微电子机械系统(MEMS)设备等先进技术由于其部件的大表面积与体积比而严重地受到摩擦和粘着的影响，从而限制了其实际应用。这笔赠款的目标是开发基于分子的润滑方案，以应对这些挑战，并促进对MEMS中润滑的基本理解。混合单层膜提供了适度的摩擦改进的潜力，集成的分子也可以作为接触下的流动润滑相。在这笔赠款中，我们将探索如何利用混合单层系统来解决MEMS设备润滑中的关键问题，方法是通过系统地调整表面化学成分来精确控制表面相互作用。这些基本的实验研究与接触的分子动力学模拟以及大规模的摩擦测量相结合，使我们能够在一系列长度尺度(nm？？m)和时间尺度(ps？？m)上探索这些现象。s)。此外，还将开发利用尖端增强拉曼光谱(TERS)来探测微器件中的粗糙-粗糙接触的新技术，其中将同时探测界面上的摩擦/粘合以及相应的局部化学变化。如果这些研究成功，那么用于MEMS器件的混合单层方案的开发可能使有源器件技术达到生产状态。参与该项目的学生(包括研究生和本科生)将接受材料科学、工程、表面化学和物理方面的多学科培训，培养他们在多个领域的熟练程度，为高级技术劳动力做好准备。这项工作的各个方面也将被纳入我们的科学和工程开放日，作为小学生的示范。与佛罗里达大学和桑迪亚国家实验室的合作互动也将允许学生在基础和应用环境中以及政府和学术实验室进行研究。

Advanced technologies such as microelectromechancial systems (MEMS) devices, suffer considerably from friction and adhesion due to the large surface to volume ratios of their components, limiting their practical applications. The goal of this grant is to develop molecular based approaches for lubrication schemes to address these challenges and advance the fundamental understanding of lubrication in MEMS. Mixed monolayer films proffer the potential of providing modest friction modification, with integrated molecules that can also function as mobile lubricant phases under contact. In this grant we will explore how mixed monolayer systems can be exploited to solve key issues in the lubrication of MEMS devices through the precise control of surface interactions by systematically tuning surface chemical composition. These fundamental experimental studies are paired with molecular dynamics simulations of the contacts, as well as large scale tribometry measurements to allow us to explore these phenomena over a range of length scales (nm ? ìm) and timescales (ps ? s). New techniques for exploring the asperity-asperity contacts that dominate microdevices, using tip enhanced Raman spectroscopy (TERS), will also be developed, where friction/adhesion and the corresponding local chemical changes at interfaces will be probed concomitantly.If these studies are successful, the development of mixed monolayer schemes for MEMS devices may enable active device technologies to reach production status. The students working on this project (both graduate and undergraduate) will receive multidisciplinary training in materials science, engineering, and surface chemistry and physics, developing proficiency in multiple arenas, preparing them for the advanced technology workforce. Aspects of the work will also be incorporated as demonstrations for elementary school students in our Science and Engineering Open House. Collaborative interactions with the University of Florida and Sandia National Labs will also allow students to conduct research in both fundamental and applied settings, as well as both government and academic labs.