Giant-Stroke, Superelastic Carbon Nanotube Aerogel Muscles
- Ali E. Aliev,
- Jiyoung Oh,
- Mikhail E. Kozlov,
- Alexander A. Kuznetsov,
- Shaoli Fang,
- Alexandre F. Fonseca,
- Raquel Ovalle,
- Márcio D. Lima,
- Mohammad H. Haque,
- Yuri N. Gartstein,
- Mei Zhang*,
- Anvar A. Zakhidov,
- Ray H. Baughman†
- The Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, TX 75083, USA.
- ↵† To whom correspondence should be addressed. E-mail: ray.baughman{at}utdallas.edu
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↵* Present address: Department of Industrial Engineering, Florida State University, Tallahassee, FL 32306, USA.
Abstract
Improved electrically powered artificial muscles are needed for generating force, moving objects, and accomplishing work. Carbon nanotube aerogel sheets are the sole component of new artificial muscles that provide giant elongations and elongation rates of 220% and (3.7 × 104)% per second, respectively, at operating temperatures from 80 to 1900 kelvin. These solid-state–fabricated sheets are enthalpic rubbers having gaslike density and specific strength in one direction higher than those of steel plate. Actuation decreases nanotube aerogel density and can be permanently frozen for such device applications as transparent electrodes. Poisson's ratios reach 15, a factor of 30 higher than for conventional rubbers. These giant Poisson's ratios explain the observed opposite sign of width and length actuation and result in rare properties: negative linear compressibility and stretch densification.
- Received for publication 10 November 2008.
- Accepted for publication 30 January 2009.
