Alcohol May Soon Power Artificial Muscles, Prosthetic Limbs

by VR Sreeraman on Jul 13 2009 4:00 PM

Instead of batteries, artificial muscles driving robots or prosthetic limbs might soon be powered by a kind of alcohol that can make people blind, say researchers.

"You can imagine robotic soldiers fighting ahead of human soldiers and getting a drink of alcohol to fight on," Live Science quoted materials scientist, Ray Baughman director of the University of Texas at Dallas NanoTech Institute as saying.

"It makes a pretty image to imagine the robot getting the alcohol from a bar, but it's not the kind of alcohol humans like," he added.

Presently, these artificial muscles work by converting electricity into mechanical energy with the help of a battery.

However, the problem is batteries neither deliver energy very quickly nor store energy efficiently given the space they occupy

Baughman suggests that instead of using batteries, artificial muscles could rely on chemical fuels like methanol, or wood alcohol, which can blind people.

"(It) has 30 times the energy storage density of a conventional battery," Baughman says.

Baughman and his colleagues have recently created an artificial muscle with the help of nickel-titanium alloy coated in platinum particles only nanometres or billionths of a meter wide.

The nanoparticles behave as catalysts, helping fuels such as methanol, hydrogen or formic acid to react with the oxygen in the air, generating heat.

The alloy does not expand when heated, unlike most materials. Instead, it contracts, generating roughly 500 times more force than natural muscles of the same diameter.

"We can generate giant forces on very short time scales," said Baughman.

However, the problem is that the muscle has to be cooled off so it can be reused.

One solution could be evaporating methanol off the system to cool the muscles down, much as evaporating sweat helps cool down human bodies.

Another issue with this muscle is that its motions can jostle the nanoparticles off.

One recent improvement to this muscle Baughman and his colleagues devised involves wrapping the muscle in a sheet of carbon nanotubes, which acts as a durable, lightweight webbing to hold the particles on.

Baughman says that if all these hurdles are overcome, these artificial muscles could find use in prosthetic limbs, exoskeletons under development to enhance human strength, droids that fly or swim, or humanoid robots.