Nanotube forms drive shaft

A researcher from the Institute of Materials Research and Engineering in Singapore has fashioned a drive shaft that is 1,000 times narrower than a human hair. The component could someday be used in machines that are smaller than bacteria.

The researcher found that briefly focusing an electron beam on a section of a multiwall carbon nanotube caused the section to widen. Carbon nanotubes are microscopic rolled-up sheets of carbon atoms that form naturally in smoke, are mechanically very strong, and have useful electrical properties. Multiwall carbon nanotubes are nested sets of tubes.

The method promises a relatively easy way to fabricate components from carbon nanotubes for use in nanoscale machines.

The researcher made a bulged-out area, or bump, on one side of a nanoube by focusing the beam on that side. By repeating the process he produced a rod with regularly spaced bumps, which could be used as a drive shaft to rotate a gear.

The researcher is now working on a carbon nanotube gear that could be combined with the drive shaft to form a nanoscale rack-and-pinon mechanism. Rack-and-pinon devices convert rotation to linear motion and vice versa.

It will be 10 or 20 years before components like the nanotube drive shaft will be ready for use in practical applications, according to the researcher. The work appeared in the February 17, 2004 issue of Nanotechnology.