Nanostructured Surfaces for Investigation of Friction at the Molecular Scale

University Of Akron, Akron OH

Investigators

Abstract

0202468 Chuang Knowledge of molecular interactions/alignment and their relations to friction between two contacting, moving surfaces are becoming important as the scale of mechanical engineering devices continues to shrink to microscopic and eventually nanoscopic scales. A lack of in situ techniques to monitor molecular interactions/alignment not only presents a challenge to understand the molecular origin of friction but also hinders the development of novel lubrication systems to minimize friction and wear. This exploratory research project proposes the development of an in situ infrared spectroscopic technique to characterize molecular interactions/alignment between two contacting, moving surfaces under working conditions with simultaneous friction measurement. The contacting surfaces will be grafted with organic molecules containing with CF3, phosphate, alkyl, aryl, ether and COOH groups. These various types of molecular surfaces allow investigation of the role of van der Walls forces, hydrophobic/hydrophilic interactions, polar functional groups, and electrostatic interactions in friction. Changes in intra- and intermolecular interactions, molecular conformation, packing, and alignment during friction measurement will be determined by the shift in molecular vibrational frequencies. This work is expected to develop a fundamental understanding of ghe friction on the moving surfaces with the well-defined molecular arrangement. This understanding coupled with the molecular grafting approach will provide a technical basis for the development of permanent, ultra low-friction coatings for moving surfaces. This type of liquid-free lubrication will provide a contaminant-free environment and eliminate the need for oil (i.e., lubricant) change. The results of this proposed study could have a far-reaching impact on the design of nanostructured surfaces for controlling friction for meso-, micro-, and macroscopic moving devices ranging from MEMS devices, artificial joints, bearings, to gears.