Tag Archives: Mechanical Resuscitation of Chemical Oscillations in Belousov–Zhabotinsky Gels

Feeling artificial skin

In reading about some of the latest work on artificial skin and feeling, I was reminded of a passage from a description of the ‘uncanny valley’ by Masahiro Mori (excerpted from my March 10, 2011 posting about robots [geminoid robots, in particular])

… this kind of prosthetic hand is too real and when we notice it is prosthetic, we have a sense of strangeness. So if we shake the hand, we are surprised by the lack of soft tissue and cold temperature.

According to a March 29, 2012 news item on Nanowerk, this state of affairs is about to change,

Sooner than later, robots may have the ability to “feel.” In a paper published online March 26 in Advanced Functional Materials (“Mechanical Resuscitation of Chemical Oscillations in Belousov–Zhabotinsky Gels”), a team of researchers from the University of Pittsburgh [Pitt] and the Massachusetts Institute of Technology (MIT) demonstrated that a nonoscillating gel can be resuscitated in a fashion similar to a medical cardiopulmonary resuscitation. These findings pave the way for the development of a wide range of new applications that sense mechanical stimuli and respond chemically—a natural phenomenon few materials have been able to mimic.

“Think of it like human skin, which can provide signals to the brain that something on the body is deformed or hurt,” says Balazs [Anna Balazs, Distinguished Professor of Chemical and Petroleum Engineering in Pitt’s Swanson School of Engineering]. “This gel has numerous far-reaching applications, such as artificial skin that could be sensory—a holy grail in robotics.”

The Pitt March 29, 2012 news release reveals some of the personal motivation behind the research,

“My mother would often tease me when I was young, saying I was like a mimosa plant— shy and bashful,” says Balazs. “As a result, I became fascinated with the plant and 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.”

Here’s a more technical description of the joint Pitt/MIT research team’s work (from the Pitt news release),

A team of researchers at Pitt made predictions regarding the behavior of Belousov-Zhabotinsky (BZ) gel, a material that was first fabricated in the late 1990s and shown to pulsate in the absence of any external stimuli. In fact, under certain conditions, the gel sitting in a petri dish resembles a beating heart.

Along with her colleagues, [Balazs] predicted that BZ gel not previously oscillating could be re-excited by mechanical pressure. The prediction was actualized by MIT researchers, who proved that chemical oscillations can be triggered by mechanically compressing the BZ gel beyond a critical stress.

I’m always fascinated by what motivates people and so Balazs’s story about the mimosa strikes me as both charming and instructive as to the sources for creative inspiration in any field.

If I read the news release rightly, we’ve still got a long way to go before ‘seeing’ robots with skin that can ‘feel’.