Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Physical Chemistry

Friction Measured A Few Atoms At A Time

Scanning probe analysis shows that forces between surfaces at the atomic scale depend on bond orientation relative to the sliding direction

by Mitch Jacoby
September 30, 2013 | A version of this story appeared in Volume 91, Issue 39

Frictional forces between surfaces sliding across each other are behind the wear and tear on things such as car engines, computer hard drives, and shoe soles. The study of these forces, called tribology, helps scientists and engineers develop longer-lasting products that require less energy to operate. Physicist A. Jay Weymouth of the University of Regensburg, in Germany, and colleagues have now pushed tribology to the atomic level for the first time. The team prepared a silicon crystal in which the orientation of silicon surface dimers in one region is perpendicular to that of an adjacent region. By using a specially equipped atomic force microscope, the team measured the drag caused by sliding the AFM tip across the different regions. They found that friction depends strongly on the orientation of the dimer bonds with respect to the sliding direction (Phys. Rev. Lett. 2013, DOI: 10.1103/physrevlett.111.126103). The technique provides an opportunity to compare quantum mechanical friction simulations, which are currently limited by computing power to a few atoms, with laboratory measurements that could not be made at the atomic scale until now.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.