Lubrication "Gaps" Aid Moving Parts.

• Position: Reducing friction - Brief Article

For decades, researchers have struggled to reduce friction in mechanical systems by improving the chemical composition of the lubricants used to separate moving parts: A study of thin-film lubricants suggests a promising new strategy. Rapidly oscillating the width of the lubricant-filled gap separating two sliding surfaces can significantly reduce friction between them. The technique keeps the lubricant in a state of dynamic disorder, preventing the formation of molecular layering that can increase friction. Based on molecular dynamics simulations, the findings would be of particular interest to designers of micro-scale machines.

"This is a novel way of controlling friction," maintains Uzi Landman, director of the Center for Computational Materials Science, Georgia Institute of Technology, Atlanta. "Through the use of small amplitude oscillations of the gap between two solid surfaces, the ordering process of the lubricant is frustrated, which maintains the lubricant in a liquid state. This allows steady motion of the surfaces with a small coefficient of friction." Varying the gap by as little as five percent can maintain the necessary level of...