Fishing line and thread used to develop superhuman muscles

Scientists have created powerful artificial muscles using ordinary fishing line and sewing thread that can generate about the same mechanical power as a jet engine and are 100 times more powerful than human muscles.

The new muscles can lift a hundred times more weight and generate a hundred times higher mechanical power than the same length and weight of human muscle.
Per weight, they can generate 7.1 horsepower per kilogramme, about the same mechanical power as a jet engine.

Researchers explain that the powerful muscles are produced by twisting and coiling high-strength polymer fishing line and sewing thread.

Scientists at University of Texas teamed with researchers in Australia, South Korea, Canada, Turkey and China to accomplish the advances.

The muscles are powered thermally by temperature changes, which can be produced electrically, by the absorption of light or by the chemical reaction of fuels.

Twisting the polymer fibre converts it to a torsional muscle that can spin a heavy rotor to more than 10,000 revolutions per minute.

Subsequent additional twisting, so that the polymer fibre coils like a heavily twisted rubber band, produces a muscle that dramatically contracts along its length when heated, and returns to its initial length when cooled.

If coiling is in a different twist direction than the initial polymer fibre twist, the muscles instead expand when heated, researchers said.

Compared to natural muscles, which contract by only about 20 per cent, these new muscles can contract by about 50 per cent of their length. The muscle strokes also are reversible for millions of cycles as the muscles contract and expand under heavy mechanical loads.

According to corresponding author Dr Ray Baughman the muscles could be used for applications where superhuman strengths are sought, such as robots and exoskeletons.

Twisting together a bundle of polyethylene fishing lines, whose total diameter is only about 10 times larger than a human hair, produces a coiled polymer muscle that can lift 16 pounds.

Operated in parallel, similar to how natural muscles are configured, a hundred of these polymer muscles could lift about 0.8 tonnes, Baughman said.

Independently operated coiled polymer muscles having a diameter less than a human hair could bring life-like facial expressions to humanoid companion robots for the elderly and dexterous capabilities for minimally invasive robotic microsurgery.

They could also power miniature "laboratories on a chip," as well as devices for communicating the sense of touch from sensors on a remote robotic hand to a human hand.

The findings are published in the journal Science.