Researchers have created some incredibly strong artificial muscles made from cheap household items. The team used fishing line and sewing thread to create muscles that can lift 100 times more weight than a human muscle of the same length and weight.
The research featured scientists from the University of Texas at Dallas’ Alan G. MacDiarmid NanoTech Institute and the ARC Center of Excellence for Electromaterials Science (ACES), located in Australia, as well as from research institutes in South Korea, Turkey, China and Canada.
According to the study’s abstract, published in the journal Science, conventional artificial muscles are limited by weight, size, dexterity and mobility. But the high-strength polymer fibers in fishing line and sewing thread do not require a motor and can be manipulated for many purposes.
To create the artificial muscles, the researchers twisted the fishing line to create a muscle that turns like a rotor and can spin. That creates a torsional, or twisting, muscle that can spin a rotor to more than 10,000 revolutions per minute, notes UT Dallas.
Extra twisting, to the point where the fishing line looks like a “heavily twisted rubber band,” creates a type of muscle with greater contraction than a human muscle. Twisting the fishing line the opposite way creates an artificial muscle that expands.
Before running off to create artificial muscles, there is a bit of a catch as heat needs to be applied to create them. The heat can be generated in a number of ways, but researchers used resistive heating, in which an electric current is sent through the metal or a conductor such as the metal lining in sewing thread. The heat helps leads to the extreme contraction when heated, up to 50 percent of the fishing line’s length compared to around 20 percent for human muscles.
According to Ray Baughman, director of the NanoTech Institute, twisting a few strands of fishing line can create a muscle that lifts 16 pounds while bundles that are designed like a muscle, containing 100 of these small fishing line muscles, can lift up to 1,600 pounds.
Researchers were at first working with carbon nanotubes, where the element's form is shaped like a tube, as this has been the go-to material for new technology research in computers, medical devices and adhesives. The fishing line was a stroke of luck for researchers and is much cheaper than nanotubes. Geoff Spinks, from ACES, said in a statement, "After nearly two decades developing exotic materials as artificial muscles, we have now discovered that the best performing systems can be made from ordinary, everyday fishing line."
The fishing line artificial muscles can be used in a variety of settings, using either a single strand or bundles of muscles. According to the researchers, a single artificial muscle can be used to create expressions in robots or in robotic microsurgery, while bundles could be used for exoskeletons or in robots used to lift heavy objects. As part of the experiment, environmental heat was used to create a mechanism that opened and closed window shutters. Researchers believe the fishing line artificial muscles could be used to develop clothing that can expand or contract based on temperature.
Video of the fishing line artificial muscles, courtesy of ACES, can be viewed below.