An Indian origin scientist at the Rensselaer Polytechnic Institute in Troy, New York, is attempting to build artificial muscles using carbon nanofibres.
Artificial muscles change length in response to a stimulus, thereby creating a smoother, more human-like motion than jerky electric motors or pneumatic devices. As such, they could be used to power robots, prosthetic limbs and artificial tissue for implantation, say scientists.
Today's most promising artificial muscles are based on electroactive polymers (EAPs) - plastics that change shape when activated electrically or with chemicals. But they lack mechanical robustness and as a result soon succumb to fatigue and fail.
To test the nanotubes ability to resist fatigue, the team led by Victor Pushparaj took a two-millimetre-square block in which many millions of nanotubes were aligned vertically, and repeatedly compressed it between two steel plates once every 0.75 seconds for over 100 hours.
The team found that even after 500,000 compressions, in which the tubes were repeatedly squashed to 75 per cent of their original length, the block kept pinging back almost to its original shape.
"The nanotubes buckled in a zig-zag shape but regained their original shapes when the load was released. The nanotubes buckled but regained their original shapes," said Pushparaj.
The findings appear in Nature Nanotechnology, reports New Scientist.