Aussies, Yanks, Canucks, and Koreans collaborate on artificial muscles

I received a media release (from the University of British Columbia [UBC]) about artificial muscles. I was expecting to see Dr. Hongbin Li’s name as one of the researchers but this is an entirely different kind of artificial muscle. Dr. Li works with artificial proteins to create new biomaterials (my May 5, 2010 posting). This latest work published in Science Express, Oct. 13, 2011,  involves carbon nanotubes and teams from Australia, Canada, Korea, and the US. From the Oct. 13, 2011, UBC media release,

An international team of researchers has invented new artificial muscles strong enough to rotate objects a thousand times their own weight, but with the same flexibility of an elephant’s trunk or octopus limbs.

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.

Here’s how the UBC media release recounts the story of these artificial muscles (Aside: The Australians take a different approach; I haven’t seen any material from the University of Texas at Dallas or the University of Hanyang),

The new material was devised at the University of Texas at Dallas and then tested as an artificial muscle in Madden’s [Associate Professor, John Madden, Dept. of Electrical and Computer Engineering] 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 Australians, not unnaturally focus on their own contributions, and, somewhat unexpectedly discuss nanorobots. From the ARC (Australian Research Council) Centre of Excellence for Electromaterials Science (ACES) at the University of Wollongong news release (?) [ETA Oct. 17, 2011: I forgot to include a link to the Australian news item; and here's a link to the Oct. 16, 2011 Australian news item on Nanowerk] ,

The possibility of a doctor using tiny robots in your body to diagnose and treat medical conditions is one step closer to becoming reality today, with the development of artificial muscles small and strong enough to push the tiny Nanobots along.

Although Nanorobots (Nanobots) have received much attention for the potential medical use in the body, such as cancer fighting, drug delivery and parasite removal, one major hurdle in their development has been the issue of how to propel them along in the bloodstream.

An international collaborative team led by researchers at UOW’s Intelligent Polymer Research Institute, part of the ARC Centre of Excellence for Electromaterials Science (ACES), have developed a new twisting artificial muscle that could be used for propelling nanobots.   The muscles use very tough and highly flexible yarns of carbon nanotubes (nanoscale cylinders of carbon), which are twist-spun into the required form.  When voltage is applied, the yarns rotate up to 600 revolutions per minute, then rotate in reverse when the voltage is changed.

Due to their complexity, conventional motors are very difficult to miniaturise, making them unsuitable for use in nanorobotics.  The twisting artificial muscles, on the other hand, are simple and inexpensive to construct either in very long, or in millimetre lengths.

Interesting, non?

There’s an animation illustrating the nanorobots and the muscles,

In the animated video below, you first see a few bacteria like creatures swimming about. Their rotating flagella are highlighted with some detail of the flagella motor turning the “hook” and “filament” parts of the tail. We next see a similar type of rotating tail produced by a length of carbon nanotube thread that is inside a futuristic microbot. The yarn is immersed in a liquid electrolyte along with another electrode wire. Batteries and an electrical circuit are also inside the bot. When a voltage is applied the yarn partially untwists and turns the filament. Slow discharging of the yarn causes it to re-twist. In this way, we can imagine the micro-bot is propelled along in a series of short spurts.

I think the graphics resemble conception complete with sperm and eggs but I can see the nanorobots too. Here’s your chance to take a look,

ETA Oct. 14, 2011 11:20 am PST: I found a copy of the University of Texas at Dallas news release posted on Oct. 13, 2011 at Nanowerk. No mention of nanobots but if you’re looking for additional technical explanations, this would be good to read.

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