Spinning Yarn Into Muscles | Science/AAAS | News

Spinning Yarn Into Muscles | Science/AAAS | News: Baughman, along with colleagues in Texas, Australia, and China, twisted plastic fibers and threads into yarns. Then when they applied heat, they found that the yarns contracted by up to 50%, a result they report today in Science. And cooling the plastic muscles returns them to their original length. Natural muscles, by comparison, only contract by 20%. 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 7.2 kilograms, the team found. Operated in parallel, an arrangement that increases their power and is similar to the way natural muscles are configured, a hundred of these polymer muscles could lift about 725 kilograms, Baughman says. Producing this force requires only off-the-shelf materials that cost about $5 per kilogram.