Oscillating gels may one day grant robots a sense of touch

Researchers at MIT and the University of Pittsburgh have successfully resuscitated non-oscillating Belousov-Zhabotinsky (BZ) gel by exerting a mechanical force: a process akin to the resuscitation of a human heart. By exhibiting a chemical response to a mechanical stimulus (a rare feat for non-living matter), it's thought the material could lead to the development of artificial skin that would enable robots to feel and self-repair. But though the application sounds similar to the bleeding, healing artificial skin we looked at last week, the science behind it is very different. "Think of it like human skin, which can provide signals to the brain that something on the body is deformed or hurt," said Anna Balazs, Distinguished Professor of Chemical and Petroleum Engineering at the Swanson School of Engineering at Pittsburgh. "This gel has numerous far-reaching applications, such as artificial skin that could be sensory - a holy grail in robotics." BZ gel, which was first fabricated in the late 1990s, pulsates by means of a Belousov–Zhabotinsky reaction (discovered by Boris Belousov in the 1950s). The oscillation of the BZ gel can be made to stop by the addition of bromide. The research team's achievement was to return such a sample to life (or the appearance of it) by applying pressure, forcing the bromide out of the gel and restarting the BZ reaction. The ability to revive BZ gel had been predicted by researchers at Pittsburgh, and now proven at MIT. Though touch-sensitive robot skin might be some way off, research at Pittsburgh continues into using BZ gels as damage sensors that could trigger a chemical reaction to instigate healing. It's also claimed that the gel could one day form the basis of robot actuators (muscles, essentially). Balazs says she has been interested in touch-sensitive materials since becoming fascinated with mimosa plants as a child. "I became fascinated with [...] its unique hide-and-seek qualities - the plant leaves fold inward and droop when touched or shaken, reopening just minutes later. I knew there had to be a scientific application regarding touch, which led me to studies like this in mechanical and chemical energy."