Tailoring carbon nanotubes

Tom Yuzvinsky

Nanotube Nanomotor

We have harnessed the atomically smooth, nested structure of a multiwalled carbon nanotube to create the world's smallest synthetic rotational motor. Unlike existing chemically driven bio-motors, our nanometer-scale electromechanical system (NEMS) actuator is designed to operate over a wide range of frequency, temperature, and environmental conditions, including high vacuum and harsh chemical environments.

After depositing multiwalled nanotubes on a silicon oxide surface, anchors and rotors made out of gold are attached to the nanotubes using electron beam lithography.   Stator electrodes are placed on either side of each rotor to provide a mechanism to drive the rotor.   Once these features are in place, the underlying silicon oxide is partially etched away to suspend the rotor and nanotube assembly.   Finally, the outer nanotube wall is severed on either side of the rotor to allow the center section to spin freely.

By applying small voltages (~1V) to the three stators (S1,S2,S3), we are able to capacitively attract the rotor into any rotary position.   Thus, the nanomotor can be driven with either DC or AC signals, and can be operated over a wide variety of environments and temperatures.

Animated image:  Walking a nanomotor through a full rotation using applied DC voltages.
Still images:  Two successive video frames of a nanomotor as it being driven by an applied AC signal.

Winner of the 2004 R&D 100 Award!

See also:

"Rotational actuators based on carbon nanotubes"
AM Fennimore, TD Yuzvinsky, WQ Han, MS Fuhrer, J Cumings and A Zettl
Nature 424, 408-410 (2003)

Featured in:
"Scientists Manufacture Nanomotor" Scientific American, 24 July 2003
"Nanomotor" Catalyst, 2 October 2003
"World's Smallest Motor" Popular Mechanics, December 2003
"Nanomotors realise visionary's dream" BBC News, 30 October 2003

To license this and similar technologies, please see the LBNL Technology Transfer website.


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