Hairlike sensors made of tiny carbon tubes and silver particles are far more sensitive than previous electronic designs for pressure detectors. The new devices mimic whiskers that cats and other animals use to sense their surroundings, and could aid human-machine interaction by helping robots sense human touch.
Scientists have previously made electronic whiskers, but they are either bulky, cannot detect ultralight touches or cannot flex repeatedly without breaking. To solve these problems, a team led by University of California, Berkeley materials scientist Ali Javey painted a film of carbon nanotubes and silver nanoparticles onto a thin, flexible strand of silicone.
To detect slight differences in pressure, the scientists applied a voltage to the strand’s base and measured how the current varied as the fiber bent slightly in wind. The film’s nanoparticles carry tiny electrical currents that change when it stretches. The nanotubes allow the film to repeatedly flex and return to its original shape.
The whiskers picked up pressures less than one-tenth as high as previous designs could detect, the researchers report January 21 in the Proceedings of the National Academy of Sciences.