In order for the new fibers to be used in prostheses, robots, exoskeletons and even clothing, three teams of researchers have developed artificial muscles They can lift 1000 times their own weight.
The muscles have all been developed according to a similar principle: that a rolled substance can stretch like a muscle. The idea was developed by Ray baughman and his colleagues at the University of Texas, who warned that twisting even a simple material such as sewing thread or fishing line can create a muscle-like structure.
Now, Baughman's team has developed stronger fibers, using equally economical materials. Bamboo or silk, for example, are wrapped in a coil and covered with a sheath that can respond to heat or electrochemical changes, which can cause the resulting muscle to contract and move.
The team hopes that its materials can be used in smart clothing that responds to the weather. In one experiment, they wove the fibers into a tissue that, as a result, responds to moisture becoming more porous.
Jinkai Yuan at the University of Bordeaux and his colleagues created their fibers with a polymer and graphene, a material stronger than diamond. Mehmet Kanik, from the Massachusetts Institute of Technology, took a different approach. His team developed a material that coils spontaneously, like the tendrils of a cucumber plant. They tested the muscle on a miniature artificial biceps based on a human arm, which lifts a weight when heat is applied.
However, there is still a long way to go in the field of efficiency: the fibers only use about 3 percent of the energy that is put into artificial muscles, while the rest is lost in the form of heat.