Who couldn’t use a little more strength? Many people without any injury or disability exercise regularly — or sometimes just pay for gym memberships — to get stronger and improve their flexibility and cardiovascular health. If you lift weights regularly for strength training, the prospect of doubling your strength in a year’s time could be enough motivation to show up consistently. Stroke victims, patients with spinal injuries, and amputees can spend months trying to regain a small fraction of their former strength and range of motion. We’ve written about various developing materials and tech for replacing muscles or enhancing strength, including MIT’s work with low-cost synthetic muscle from nylon fiber and coiled nylon artificial muscle development at the University of Texas in Dallas.
Researchers at the University of Illinois Department of Mechanical Science and Engineering pressed the bar for artificial muscle development to a level previously unforeseen. Working with coiled carbon fiber-reinforced rubber, the group developed carbon fiber muscles that can lift up to 12,600 times their weight. Activated by tiny amounts of electrical current, the researchers demonstrated lifting a half gallon of water 1.4 inches with just 0.172 V/cm of applied voltage. Referring to others’ work with coiled nylon fiber, the University of Illinois team focused on increasing fiber strength exponentially. Carbon fiber dipped in polydimehtylsiloxane (PDMS) was twisted with a hand drill to create coiled yarn. In their study published in Smart Materials and Structures, the researchers demonstrated the carbon fiber thread’s ability to apply large contractile strokes and lift heavy weights.
Applications for artificial muscles include robotics, prosthetics, orthotics, and human assistive devices. The carbon fiber threads are relatively easy and inexpensive to produce and can be activated by electricity, heat, or induced chemical swelling. The work of the University of Illinois team and others could conceivably result in assistive devices for a wide range of purposes. However, it’s not likely the material will help with that toughest of all physical conditioning exercises, the “Refrigerator Push-off.”