Quartz Crystal Microbalance Studies of Atomic-Scale Friction

技术上，20世纪末标志着摩擦学基础领域的复兴，新的实验和理论技术能够研究原子尺度上定义良好的几何图形中的摩擦力。这个项目涉及使用一种这样的技术，即石英晶体微天平，来探索这一领域的关键课题。第一组实验将探索摩擦如何影响聚苯乙烯微球的定向运输，以记录通过原子尺度摩擦水平的变化对运动的控制。第二个涉及滑动对单层厚氪层二维熔点的影响的研究，这对温升和热传输的基础研究很重要。最后一组实验将记录磁场如何影响氦和氧薄膜中牢固确立的、但仍鲜为人知的超导摩擦现象。我们的目标是加深我们对滑动摩擦中电子对能量耗散机制的贡献的知识。免费教育的组成部分包括：(1)本科生持续参与研究；(2)将最新的摩擦信息直接传播给制定该主题课程的教师，以及通过讲座和书面评论向更多的普通受众传播。根据最新估计，提高对摩擦和磨损的关注将为发达国家节省高达1.6%的国民生产总值(GDP)，仅在美国每年就超过1000亿美元。随着能源价格的上涨，节约能源和原材料的需求变得越来越迫切，物理学家们急于了解基本摩擦学过程的速度预计只会加快。20世纪末标志着摩擦学基础领域(摩擦和磨损研究)的复兴，许多新的实验和理论技术能够研究纳米尺度上明确定义的几何中的摩擦力。该项目涉及使用一种这样的技术，即石英晶体微天平(QCM)，(1)探索摩擦对控制微米级粒子的作用，这是新兴纳米技术领域的一个重要特征，包括医疗、电子和制造应用，(2)探测简化的滑动接触的温度，这个量从理论、实验和计算方法都极难量化，以及(3)探索与超导有关的摩擦现象，这种现象已经确立，但仍然知之甚少。我们的目标是加深我们对电子如何造成能量损失的基础知识。免费教育部分包括(1)本科生持续参与研究，(2)直接向制定该主题课程的教师传播关于摩擦的最新信息，以及通过讲座和书面评论向更广泛的受众传播。

TechnicalThe late 20th century marked a renaissance in fundamental areas of tribology, sparked by new experimental and theoretical techniques capable of studying the force of friction in geometries which are well defined at the atomic scale. This project involves the use of one such technique, namely the Quartz Crystal Microbalance, to probe critical topics in this field. A first set of experiments will explore how friction impacts directed transport of polystyrene microspheres, to document control of motion through variations in atomic-scale friction levels. The second involves studies of the impact of sliding on the two-dimensional melting point of monolayer thick Krypton layers, important for fundamental studies of temperature rise and heat transport. The final set of experiments will document the manner in which magnetic fields influence the firmly established, yet still poorly understood phenomenon of superconductivity-dependent friction, for helium and oxygen films. The goal is to deepen our knowledge of electronic contributions to energy dissipation mechanisms in sliding friction. A complimentary educational component includes (1) ongoing participation of undergraduates in the research, and (2) direct dissemination of state-of-the-art information on friction to instructors developing curriculum on the topic, as well as to more general audiences through lectures and written reviews.Non-TechnicalBy most recent estimates, improved attention to friction and wear would save developed countries up to 1.6% of their gross national product, well over $100 billion annually in the U.S. alone. As the price of energy rises, and the need to conserve both energy and raw materials becomes increasingly urgent, physicists' rush to understand basic tribological processes can only be expected to accelerate. The late 20th century marked a renaissance in fundamental areas of tribology (the study of friction and wear), sparked by a number of new experimental and theoretical techniques capable of studying the force of friction in geometries which were are well-defined at the nanometer scale. This project involves the use of one such technique, namely the Quartz Crystal Microbalance (QCM), (1) to explore the role of friction to control micron scale particles, an important feature in emerging nano-technological areas that include medical, electronic and manufacturing applications, (2) to probe the temperature of a simplified sliding contact, a quantity that has been exceptionally difficult to quantify from theoretical, experimental and computational approaches, and (3) to explore the firmly established, yet still poorly understood phenomenon of superconductivity-dependent friction. The goal is to deepen our fundamental knowledge of how electrons contribute to energy loss. A complimentary educational component includes (1) ongoing participation of undergraduates in the research, and (2) direct dissemination of state-of-the-art information on friction to instructors developing curriculum on the topic, as well as to more general audiences through lectures and written reviews.