An international team has unmasked the hidden superpowers of humble sewing thread and fishing line. Twisting nylon and polyethylene into coils, they made artificial muscles that can lift loads over 100 times heavier than human muscle of the same length and weight. They could replace motors in many uses, particularly robotics, and enable new technologies, such as smart clothing, says Ray Baughman from the University of Texas, Dallas. He is also excited that the threads used cost just US$5/kg. ‘They could be easily deployed in the developing world, children could make and use them,’ he tells Chemistry World.
SRI has patented a thin, flexible, smart material dubbed “artificial muscle” because it behaves much like a human muscle. Artificial muscle, available for license from SRI for a variety of application areas, uses a breakthrough technology called electroactive polymers. The material expands when exposed to an electric current and contracts when the electricity is removed, converting electrical potential energy into mechanical motion. Artificial muscle has the potential to fundamentally shift the way many types of industrial, medical, consumer, automotive and aerospace products are powered and operated. It offers significant advantages over typical electromagnetic-based technologies because it is much lighter, smaller, quieter and cheaper. It also offers more controllable and flexible configurations. Artificial muscle enables a wide variety of applications, including haptic displays to improve human computer interaction, adaptive optics, flat conformal loudspeakers, and, potentially, implantable active medical prosthetics. The technology has also demonstrated promise for a variety of actuator and electric power generation applications. Because of its inherent muscle-like characteristics, SRI’s artificial muscle can enable robots to mimic the dexterity and mobility of humans. It offers performance characteristics similar to those of natural muscle such as high strain, high peak power and high compliance. In addition to acting as a muscle-like actuator, artificial muscle can operate in reverse and generate power from being stretched and contracted. Compared to many other smart material technologies, the polymer materials used in artificial muscle are relatively inexpensive. Their high compliance allows artificial muscle to easily interface with human or other environmental sources of motion. Combined with its high energy output, these features make it attractive for a variety of energy harvesting applications, such as capturing the energy of ocean waves. In 2008, SRI first demonstrated a wave-powered generator that converts energy from ocean waves to electrical energy. In 2005, SRI spun off Artificial Muscle Inc. (AMI), to further develop the technology and introduce products based on EPAM. In 2010, AMI became a subsidiary of Bayer MaterialScience LLC.