Artificial Muscles from Fishing Line and Sewing Thread

 

Science 21 February 2014:Vol. 343 no. 6173 pp. 845-846 
DOI: 10.1126/science.1250471
PERSPECTIVE

MATERIALS SCIENCE

Fibers Do the Twist

1. Jinkai Yuan, 
2. Philippe Poulin

+Author Affiliations

1. Centre de Recherche Paul Pascal, CNRS, Université de Bordeaux, 115 Avenue Schweitzer, 33600 Pessac, France.

1. E-mail: poulin@crpp-bordeaux.cnrs.fr

In a rubber band–powered airplane, a pretwisted band untwists when the hook used to initially balance its torque is released (see the figure). Such an actuation is based on the elastic recovery of the stretched polymer chains. The material has to be mechanically retwisted to operate but the method is simple and efficient, because the rubber band delivers almost as much energy as needed to twist it. Unfortunately, soft rubber cannot easily provide large stress and cannot be used in modern applications such as robotics, artificial muscles, smart textiles, and new medical devices. But as Haines et al. show on page 868 of this issue (1), the concept of twisted fibers can nevertheless be useful in demanding actuator applications.

http://www.sciencemag.org/content/343/6173/845.summary

Science 21 February 2014: 
Vol. 343 no. 6173 pp. 868-872 
DOI: 10.1126/science.1246906
REPORT

Artificial Muscles from Fishing Line and Sewing Thread

1. Carter S. Haines1, 
2. Márcio D. Lima1, 
3. Na Li1, 
4. Geoffrey M. Spinks2, 
5. Javad Foroughi2, 
6. John D. W. Madden3,
7. Shi Hyeong Kim4, 
8. Shaoli Fang1, 
9. Mônica Jung de Andrade1, 
10. Fatma Göktepe5, 
11. Özer Göktepe5,
12. Seyed M. Mirvakili3, 
13. Sina Naficy2, 
14. Xavier Lepró1, 
15. Jiyoung Oh1, 
16. Mikhail E. Kozlov1, 
17. Seon Jeong Kim4,
18. Xiuru Xu1,6, 
19. Benjamin J. Swedlove1, 
20. Gordon G. Wallace2, 
21. Ray H. Baughman1,*

+Author Affiliations

1. ¹The Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, TX 75083, USA.
2. ²Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, New South Wales 2522, Australia.
3. ³Department of Electrical and Computer Engineering and Advanced Material and Process Engineering Laboratory, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
4. ⁴Center for Bio-Artificial Muscle and Department of Biomedical Engineering, Hanyang University, Seoul 133-791, South Korea.
5. ⁵Department of Textile Engineering, Çorlu Engineering Faculty, Namık Kemal University, Çorlu-Tekirdağ, Turkey.
6. ⁶Alan G. MacDiarmid Institute, Jilin University, Changchun 130012, China.

1. ↵*Corresponding author. E-mail: ray.baughman@utdallas.edu

• ABSTRACT
• EDITOR'S SUMMARY

The high cost of powerful, large-stroke, high-stress artificial muscles has combined with performance limitations such as low cycle life, hysteresis, and low efficiency to restrict applications. We demonstrated that inexpensive high-strength polymer fibers used for fishing line and sewing thread can be easily transformed by twist insertion to provide fast, scalable, nonhysteretic, long-life tensile and torsional muscles. Extreme twisting produces coiled muscles that can contract by 49%, lift loads over 100 times heavier than can human muscle of the same length and weight, and generate 5.3 kilowatts of mechanical work per kilogram of muscle weight, similar to that produced by a jet engine. Woven textiles that change porosity in response to temperature and actuating window shutters that could help conserve energy were also demonstrated. Large-stroke tensile actuation was theoretically and experimentally shown to result from torsional actuation.

http://www.sciencemag.org/content/343/6173/868

Paying Graduate School's Mental Toll

Science Home » Science Careers » Career Magazine » Previous Issues » 2014 » February 04

Life and Career

Paying Graduate School's Mental Toll

By

Carrie Arnold

February 04, 2014

About 60% of graduate students said that they felt overwhelmed, exhausted, hopeless, sad, or depressed nearly all the time. One in 10 said they had contemplated suicide in the previous year.

Like nearly all science graduate students, chemistry blogger See Arr Oh was no stranger to stress. But one afternoon during his third year of a Ph.D. program in organic chemistry, as he sat in his car, he decided the stress might actually be killing him. "All of a sudden I would just be blurred out and tense all over. Everything just seemed to rush at me at once," he says. He went to the emergency room and was told he was suffering from panic attacks.

http://sciencecareers.sciencemag.org/career_magazine/previous_issues/articles/2014_02_04/caredit.a1400031