Super-stretchy skin-like sensor uses nanotube springs
October 25, 2011
Stanford University’s Zhenan Bao, associate professor of chemical engineering, has developed a transparent film of single-walled carbon nanotubes that act as tiny springs that accurately measure the force applied.
The sensors could be used in making touch-sensitive prosthetic limbs or robots, in touch screens on computers, or for various medical applications such as pressure-sensitive bandages.
“This sensor can register pressure ranging from a firm pinch between your thumb and forefinger to twice the pressure exerted by an elephant standing on one foot,” said Darren Lipomi, a postdoctoral researcher in Bao’s lab, who is part of the research team.
The sensors consist of two layers of nanotube-coated silicone, oriented so that the coatings are face-to-face, with a layer of a more easily deformed type of silicone between them. The middle layer of silicone act as a capacitor, storing electrical charge, like a battery. When pressure is exerted on the sensor, the middle layer of silicone compresses, which alters the amount of electrical charge it can store. That change is detected by the two films of carbon nanotubes, which act as electrodes that can connect to voltage measuring devices.
Ref.: Darren J. Lipomi, et al., Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes, Nature Nanotechnology, 2011; [doi:10.1038/nnano.2011.184]