Possible lightweight, powerful and energy efficient synthetic muscle production using carbon nanotubes.
Related in composition to aerogel, its density is around 1.5 mg/cm3 and in relation to muscular actions, its rate of expansion when placed under electrical current is 37,000% per second compared with the 50% rate of expansion per second of biological muscle.
"When most materials are pulled in one direction, they get thinner in the other direction, similar to how a rubber band behaves when it is stretched. However, specially designed carbon nanotube sheets, dubbed “buckypaper,” can increase in width when stretched. The buckypaper can also increase in both length and width when uniformly compressed."