Benjamin Mattes, CEO of Santa Fe Science and Technology, is building strong, long-lasting artificial muscles out of conducting polymers that expand and contract in response to changes in the flow of ions into the materials. These electroactive polymers generate huge forces at low voltages. Because chemical reactions break down the polymer, earlier versions were slow and able to survive only a few cycles. Mattes’s latest device, however, smashes previous records for speed and durability. Its coaxial structure-tiny fibers threaded through a hollow tube and engulfed in liquid electrolyte-allows ions to flow rapidly into the fibers in response to applied voltage. Because he uses a highly stable and conductive ionic liquid as the electrolyte, Mattes says he has achieved “millions of cycles without degradation.”
Thanks to such advances in materials science, electroactive polymers are starting to yield useful biomedical devices. At the University of New Mexico, Shahinpoor has demonstrated thin, durable artificial muscles that can lift many times their own weight. Shahinpoor is using the materials to develop implantable aids such as a pump that works like a mechanical pacemaker to compress the heart and a tiny device that corrects vision by gently squeezing the eyeball. His team is commercializing the devices through a spinoff, Environmental Robots in Albuquerque, NM.
There is plenty of work to do before the technology will be ready for market, however. To be successful, Shahinpoor says, the company will need to ensure that the materials are compatible with living tissue and that their functions can be precisely controlled. He will also need to cut manufacturing costs by a factor of 10.
Although the next five years should see electroactive polymers used as components in microsurgical tools, drug delivery systems, and corrective aids, such advances may be only a beginning. To achieve more lifelike robots and prosthetic devices, scientists will need to make materials that are smarter and more interactive. Within 10 years, researchers aim to develop artificial limbs that provide feedback to the user, graceful autonomous robots that are powered by musclelike polymers, and even suits that enhance the strength and endurance of soldiers and rescue personnel. If the research is successful, robotics may truly come to life.