UT Dallas researchers have made artificial muscles from carbon nanotube yarns that have been infiltrated with paraffin wax and twisted until coils form along their length. The diameter of this coiled yarn is about twice the width of a human hair. (Source UT Dallas)
New artificial muscles made from nanotech yarns and infused with paraffin wax can lift more than 100,000 times their own weight and generate 85 times more mechanical power than the same size natural muscle, according to scientists at The University of Texas at Dallas and their international team from Australia, China, South Korea, Canada and Brazil. The artificial muscles are yarns constructed from carbon nanotubes, which are seamless, hollow cylinders made from the same type of graphite layers found in the core of ordinary pencils. Individual nanotubes can be 10,000 times smaller than the diameter of a human hair, yet pound-for-pound, can be 100 times stronger than steel.The new artificial muscles are made by infiltrating a volume-changing “guest,” such as the paraffin wax used for candles, into twisted yarn made of carbon nanotubes. Heating the wax-filled yarn, either electrically or using a flash of light, causes the wax to expand, the yarn volume to increase, and the yarn length to contract. The combination of yarn volume increase with yarn length decrease results from the helical structure produced by twisting the yarn. A child’s finger cuff toy, which is designed to trap a person’s fingers in both ends of a helically woven cylinder, has an analogous action. To escape, one must push the fingers together, which contracts the tube’s length and expands its volume and diameter. In the video below, Dr. Ray Baughman of UT Dallas’s NanoTech Institute explains carbon nanotube yarns.