From Our 2010 Archives
Researchers Develop Touch-Sensitive 'e-Skin'
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MONDAY, Sept. 13 (HealthDay News) --Sure, industrial robots can toss around 10-ton car parts with the greatest of ease. But can they do the dishes?
Maybe so, say researchers, but you'd need one with "skin" -- that is, with appendages using a pressure-sensitive technology that allow them to adjust to the differing amounts of force needed to handle everything from a heavy NASCAR engine to a delicate soft-boiled egg.
Now a team led by Ali Javey, an associate professor of electrical engineering and computer sciences at the University of California, Berkeley, says they are working on just that: developing a flexible, touch-sensitive, futuristic artificial skin out of wholly inorganic semiconductors.
Dubbed the "e-skin", the technology is made up of hair-thin miniaturized strips of low-voltage nanowire transistors based on entirely inorganic materials such as crystalline silicon.
"The idea is to have a material that functions like the human skin, which means incorporating the ability to feel and touch objects," Javey said in a news release .
Javey and his UC team report on the progress of their work on e-skin in the current advanced online edition of the journal Nature Materials.
Using an innovative fabrication technique, Javey and his team rolled and "printed" nanowires onto bendable sheets of poylimide film, in an effort to create 18 by 19 pixel square matrixes comprised of hundreds of semiconductor nanowires. The process was compared to a lint roller in reverse, which, rather than picking up fibers, deposited nanowire "hairs" onto a sticky substrate.
In turn, these seven-centimeter-thick squares were then integrated with a thin pressure-sensitive rubber material.
The final product: an artificial skin fashioned into glove-like proportions that runs on less than five volts of power and can detect a range of pressure suitable for anything from typing on a keyboard to holding an object.
To date, testing shows that the e-skin can maintain functionality even after 2000 bending cycles, the authors noted.
Javey and his colleagues hope that the innovation could eventually be developed to help restore a sense of touch to patients with prosthetic limbs.
This long-range goal, however, would require many more major technological advances in order to enable researchers to integrate e-skin sensors with an individual's nervous system.
Meanwhile, the team will continue its work, funded in part by the National Science Foundation and the Defense Advanced Research Projects Agency, to refine its electronic skin for a range of possible uses.
"It's a technique that can be potentially scaled up," post-doctoral fellow and study lead author Kuniharu Takei said in the release. "The limit now to the size of the e-skin we developed is the size of the processing tools we are using."
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SOURCES: Nature Materials online, Sept. 9, 2010, news release.