Bearings on a molecular scale, or nanobearings, have been receiving an escalating level of attention from research and commercial communities worldwide. Recent developments offer a glimpse into the likely future of this increasingly important segment of the bearing industry's long-term future -- bearings which tantalizingly offer near-frictionless, wear-free performance in the smallest possible mechanical devices.

Nanotubes are hollow cages of carbon atoms several nanometers (1 nanometer = 1 billionth of a meter) thick and up to several thousand nanometers long. It would take a pile of 10,000 nanotubes to stretch across the diameter of a human hair.

In 2000, researchers at the University of California, Berkeley, were among the first to assemble these nearly frictionless bearings by nesting carbon nanotubes. In that instance, a scanning-tunneling microscope and transmission electron microscope (TEM) at Lawrence Berkeley National Laboratory were used to peel the tips off of three-level carbon nanotubes, then nesting the two in an inner and outer.

The question of why no "lubrication" is needed for near-frictionless performance is most likely answered by the behavior of intermolecular or Van der Waals force [Wikipedia: Van der Walls force].

Mass-produced nanobearings will enable the development of increasingly sophisticated and commercially viable nanoelectromechanical systems (NEMS).

ETH-Zurich's Institute of Robotics and Intelligent Systems [website] has now successfully completed mass production of nanobearings composed of multiwalled carbon nanotubes assembled in parallel via dielectrophoresis [Wikipedia: dielectrophoresis].

This is likely the first nanobearing production process which has the potential for scaling up to become commercially viable.

The "core-shell" nested nanotube construction not only behaves like a bearing but also like a spring, and can be energized to act as electromechanical actuators or relays.