Stretch Armstrong is a reality — sort of.
Stanford University researchers have developed artificial skin that can be stretched to more than twice its normal length in any direction and return to its original form, sans wrinkles or permanent damage.
Professor Zhenan Bao’s “super skin” is really a pressure sensor, which uses a transparent film of single-walled carbon nanotubes to accurately measure force applied to it, whether a squeeze or a stretch.
Bao, working with researchers Darren Lipomi, Michael Vosgueritchian and Benjamin Tee, seeks to use the sensor for robots or various medical applications, from touch-sensitive prosthetic limbs to pressure-sensitive bandages.
The key to the sensor is those nanotubes, which the researchers sprayed in a liquid suspension onto a thin layer of silicone. When applied to the silicone, they arrange themselves in an ad hoc fashion; when stretched, the bundles align. Once the silicone rebounds to its original shape, the nanotubes buckle, forming spring-like shapes that allow the material to be stretched over and over without permanent deformation.
Better still, that first stretch does not significantly impact the electrical conductivity of the material, ensuring that the material can store electrical charge and preserving the sensor’s ability to transmit information.
The change sensed by the nanotube films is what enables the sensor to transmit what it is “feeling.”
The researchers previously created a fixed sensor so sensitive that it could detect the pressure of a common bluebottle fly; they’re now working on bringing this new flexible, transparent version up to that level of sensitivity.
Their work was published in the journal Nature Nanotechnology.
