Friction is reduced when the tip of an atomic force microscope is vibrated as it moves across a surface. Red represents areas of high friction, blue low. (Courtesy of Anisora Socoliuc, University of Basel)
Nano Lube for NEMS
A new way to reduce friction could make nanomachines practical
Source: “Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts”
Anisoara Socoliuc et al.
Science 313: 207-210
Results: Researchers at the University of Basel, Switzerland, have created a practical form of lubrication for nanoscale electromechanical systems (NEMS) that reduces friction between the devices’ tiny moving parts 100-fold. The new method is needed because liquid lubricants do not work at the nanoscale, and other dry approaches to reducing friction have been too difficult to use in experimental nanomechanical devices.
Why it matters: Some of the most promising nanotechnologies involve micro- and nanoelectromechanical devices, including microscopic mirrors for communications routers and ultradense computer memory that uses the tip of an atomic force microscope (AFM) to write data bits. But friction can cause the mechanical parts in these devices to wear out too quickly, limiting their commercial use.
Methods: When researchers move a microscopic tip across a surface to make nano features, friction causes the tip to alternately stick and slip. The Swiss team eliminated this problem by vibrating the tip of a silicon AFM probe, reducing the friction between it and test surfaces of sodium chloride and potassium bromide. The application of this technique would be straightforward in AFM-based memory; other NEMS devices could incorporate small oscillators to vibrate parts that might stick.
Next steps: The researchers recently tested their method on oxidized silicon in air, and initial results suggest that it works. But they still need to apply the technique to existing devices.