In a paper published online today on Science Express, the scientists and engineers from the University of British Columbia, the University of Wollongong in Australia, the University of Texas at Dallas and Hanyang University in Korea detail their innovation. The study elaborates on a discovery made by research fellow Javad Foroughi at the University of Wollongong.
Using yarns of carbon nanotubes that are enormously strong, tough and highly flexible, the researchers developed artificial muscles that can rotate 250 degrees per millimetre of muscle length. This is more than a thousand times that of available artificial muscles composed of shape memory alloys, conducting organic polymers or ferroelectrics, a class of materials that can hold both positive and negative electric charges, even in the absence of voltage.
“What’s amazing is that these barely visible yarns composed of fibres 10,000 times thinner than a human hair can move and rapidly rotate objects two thousand times their own weight,” says Assoc. Prof. John Madden, UBC Dept. of Electrical and Computer Engineering.
Madden says, “While not large enough to drive an arm or power a car, this new generation of artificial muscles – which are simple and inexpensive to make – could be used to make tiny valves, positioners, pumps, stirrers and flagella for use in drug discovery, precision assembly and perhaps even to propel tiny objects inside the bloodstream.”
Central to the team’s success are nanotubes that are spun into helical yarns, which means that they have left and right handed versions, which allows the yearn to be controlled by applying an electrochemical charge, and to twist and untwist.
The new material was devised at the University of Texas at Dallas and then tested as an artificial muscle in Madden’s lab at UBC. A chance discovery by collaborators from Wollongong showed the enormous twist developed by the device. Guided by theory at UBC and further experiments in Wollongong and Texas, the team was able to extract considerable torsion and power from the yarns.
The torsional rotation of helically wound muscles, such as those in the flagella of bacteria, has existed in nature for hundreds of millions of years. Many other natural appendages – from the trunk of an elephant to octopus’s powerful and limber tentacles – also show how helically wound muscle fibers cause rotation by contracting against a boneless core.
The nanotube yarns are activated by charging them in a salt solution, much as a battery is charged. A breakthrough discovery came from former UBC PhD student Tissaphern Mirfakhrai – now at Stanford – who found that the deformation of the yarns is proportional to the size and number of ions inserted. A similar effect is seen in lithium ion battery electrodes used in portable electronic devices, but in yarns it is put to good use. The helical structure of the yarns makes them unwind as they accept charge and swell. They twist back up again when discharged.
“The discovery, characterization, and understanding of these high performance torsional motors show the power of international collaborations,” says corresponding author Ray Baughman, Robert A. Welch Professor of Chemistry and director of the University of Texas at Dallas Alan G. MacDiarmid NanoTech Institute.
Support for this research includes a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada.
To view animation that shows potential application for the artificial muscles, visit: http://electromaterials.edu.au/news/UOW112032
Lorraine Chan | EurekAlert!
Robocabs: The mobility of the future?
25.06.2019 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO
Self-organising system enables motile cells to form complex search pattern
07.05.2019 | Westfälische Wilhelms-Universität Münster
From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.
Reducing machine downtime, manufacturing defects, and excessive scrap
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
25.06.2019 | Power and Electrical Engineering
25.06.2019 | Studies and Analyses
25.06.2019 | Health and Medicine