for National Geographic News
It's hundreds of times thinner than a human hair but as sensitive as a human finger.
Researchers have devised a "nanosheet" that can be wrapped around any surfacesuch as that of a surgical instrument or a robotic handto mimic the sensitivity of touch.
(Related: "Fake Skin Gives Robots Sense of Touch" [August 17, 2005].)
The sensitive sheet was produced by encouraging microscopic particles to bond to the sensor surface by dipping the materials in a series of chemical baths.
The resulting material is only about a hundred nanometers, or a hundred-billionths of a meter, thick. (Video: Nanotechnology: The New Plastic.)
The nanosheet is essentially an electric sandwich of metal layers and semiconducting particles.
When something touches it, the pressure changes the current in the sheet, and the affected particles in the sheet light up.
In a demonstration, this light pattern was captured by a miniscule camera, which transmitted the image to a viewing screen.
Vivek Maheshwari, at the University of Nebraska in Lincoln, and Ravi Saraf, at the Virginia College of Osteopathic Medicine in Blacksburg, led the research. Their work will appear in tomorrow's issue of the journal Science.
Touching Without Touching
Saraf says the new sensor technology overcomes two long-standing hurdles: It drastically refines the scale of sensitivity from the range of about two millimeters to the resolution of human touch. And it's a flexible sheet, so it avoids the old clumsiness of trying to fit more rigid material to a complex surface, like that of a robot's "finger."
"It's almost like a paint," he said. "You can deposit this on any surface you like."
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