Scientists have developed artificial carbon nanotube muscles that are 200 times stronger than the human muscle fibers of the same size. They can support about 50,000 times their own weight as reported by the researchers at the University of Texas at Dallas.
This research has been published online in the journal Science.
Individually, these tiny nanotubes can be 10,000 times smaller than the diameter of the human hair and pound-for-pound, they can be 100 times than that of steel in strength.
These tiny strong muscles can be powered by electricity or light and can be used as actuators in robotics and surgical tools, and they can drive tiny motors and flywheels.
“The artificial muscles that we’ve developed can provide large, ultrafast contractions to lift weights that are 200 times heavier than possible for a natural muscle of the same size,” Dr. Ray Baughman, team leader, Robert A. Welch Professor of Chemistry and director of the Alan G. MacDiarmid NanoTech Institute at UT Dallas, said in a statement.“While we are excited about near-term applications possibilities, these artificial muscles are presently unsuitable for directly replacing muscles in the human body.”
They can also contract like muscles at very high speeds in response to light and certain chemicals. In order to demonstrate this, researchers heated them briefly. Upon heating paraffin wax expanded becoming fatter and shorter pushing against the nanotube walls. Upon cooling the fiber again, it shrank and nanotubes became narrower and longer. This contraction and expansion of the fiber took about 25 milliseconds.
Interestingly, these carbon nanotube muscles don’t require battery-like electrolytes to function. Scientists have found that these tiny muscles could work at the temperature as high as 2,500 degrees Celsius.
“The remarkable performance of our yarn muscle and our present ability to fabricate kilometer-length yarns suggest the feasibility of early commercialization as small actuators comprising centimeter-scale yarn length,” Baughman said. “The more difficult challenge is in upscaling our single-yarn actuators to large actuators in which hundreds or thousands of individual yarn muscles operate in parallel.”
Márcio D. Lima, Na Li, Mônica Jung de Andrade, Shaoli Fang, Jiyoung Oh, Geoffrey M. Spinks, Mikhail E. Kozlov, Carter S. Haines, Dongseok Suh, Javad Foroughi, Seon Jeong Kim, Yongsheng Chen, Taylor Ware, Min Kyoon Shin, Leonardo D. Machado, Alexandre F. Fonseca, John D. W. Madden, Walter E. Voit, Douglas S. Galvão, Ray H. Baughman, (2012). Electrically, Chemically, and Photonically Powered Torsional and Tensile Actuation of Hybrid Carbon Nanotube Yarn Muscles. Science, DOI: 10.1126/science.1226762