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Self-Healing Artificial Muscles
Valor1016 writes "Researchers in California have developed an artificial muscle that heals itself and generates electricity. 'We've made an artificial muscle that, when you apply electricity to it, it expands, more than 200 percent, the motion and energy is a lot like human muscles,' said Qibing Pei, a scientist at UCLA and study author. The researchers used flexible carbon nanotubes as electrodes. If an area of the carbon nanotube fails, the region around it seals itself by becoming non-conductive and prevents the damage from spreading to other areas. This material also conserves about 70% of the energy you put into it. As the material contracts after an expansion the rearranging of the carbon nanotubes generates a small electric current that can be captured and used to power another expansion or stored in a battery. The research appeared in the January issue of Advanced Materials."
One big question about artificial muscles is about the time required for the muscle to contract. One can make an artificial muscle out of an aligned block copolymer, but it would generally take hours to do anything after the electric potential is applied.
Reversibility, flexibility, bio-compatibility, and tensile strength are also important considerations. When the article is published in Advanced Materials, I'm actually going to read it to find out.
It sounds similar to the rip-proof diamond weave fabric used for hot air balloons. You can cut/puncture it, but the damage will stay isolated. Still, it's far better than the normal situation in these cases where surrounding material near the defect, because it's all interdependent, becomes weaker and perpetuates the damage.
He's getting rather old, but he's a good mouse.
Since muscle expansion and contraction is always referenced in the direction of force, the article disagrees with you.
The power stroke for a biological muscle is the contraction. While these "muscles" are interesting and could have many uses, powering limbs is not likely to be one in their current configuration.
"As the material contracts after an expansion the rearranging of the carbon nanotubes generates a small electric current that can be captured and used to power another expansion or stored in a battery."
The other expansion should not be of the same muscle, of course; alternate between two opposing muscles and you can get a very efficient walking motion going.
(I said "walking," dammit, not "wanking!")
All of the posts complaining that "muscles should contract, not expand" -- hey, it's not that hard to use an expansion to create a useful pulling force. Wrap an elastic sleeve around it that will get shorter as it gets rounder, and mechanically it will work very much like a muscle.
"Ain't no right way to do a wrong thing."