CAREER: The Dependence of Friction on Vibrations at the Atomic Scale: A Fundamental Study Using Isotopic Engineering

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

CAREER: The Dependence of Friction on Vibrations at the Atomic Scale: A Fundamental Study Using Isotopic Engineering Robert W. Carpick University of Wisconsin - Madison Research Much progress has been made in the long-standing engineering discipline of tribology - the study of friction, adhesion, lubrication, and wear - yet many key questions remain. Recently, tribology has emerged as critically important to the field of nanotechnology, since the increased surface-to-volume ratio at small scales ensures that surface or interface effects dominate the interactions between micro- or nano-scale components. Therefore, progress toward the implementation of nano-scale materials technologies will not occur without a fundamental atomic-scale understanding of the tribological properties of interfaces. The proposed research will address this knowledge gap by studying a fundamental aspect of tribology: the relationship between frictional energy dissipation and the vibrational properties of materials. Specifically, the PI will perform atomic force microscope (AFM) measurements of friction at the atomic scale as a function of isotopic composition of the sliding materials. The substitution of heavier stable isotopes is a method to tailor specific vibrational properties by changing the mass, but not the chemical identity, of atoms in a material. The impact of this research will be: (1) to provide a quantitative experimental basis that will critically enhance the theoretical understanding of frictional energy dissipation in terms of vibrational energy; and (2) to enable the design of nanostructured materials and devices with optimized tribological (and other) properties via isotopic engineering. Education and Outreach To be prepared for new opportunities in nanotechnology, engineering programs must incorporate previously non-traditional physical and experimental concepts into the curriculum. The PI will make a major contribution to this by: (1) expanding an engineering mechanics undergraduate laboratory course to include a battery of nano-scale experiments including AFM experiments; and (2) co-developing an advanced seminar course in nanotechnology directed at engineers. The intention is not simply to provide new course materials locally, but to have these materials serve as models for enhancing engineering curricula everywhere through evaluation and wide dissemination on the web, education publications, and in public meetings. In addition, outreach efforts aimed at the general public and K-12 students will be pursued. The PI will contribute to the design of an upcoming international science museum exhibit on materials science by developing modules (visualization, models, hands-on materials) on the topics of microscopy, friction, and isotopes. The PI will also develop a classroom-compatible macro-scale AFM made of simple and affordable components which can demonstrate concepts behind high resolution imaging and friction force measurements. Local impact of this work will be felt through the PI's active involvement in a successful minority university recruiting program at UW-Madison. Finally, building on the established practice in the PI's lab, the laboratory efforts will also include substantial involvement of undergraduates including members of underrepresented groups.