In today’s Academic Minute, Dr. Anna Balazs of the University of Pittsburgh explains how a synthetic material could provide robots with a sense of touch.
Dr. Anna Balazs is a distinguished professor of Chemical and Petroleum Engineering at the University of Pittsburgh. Her research interests center on theoretical and computational modeling of the thermodynamic and kinetic behavior of polymer blends and composites. She holds a Ph.D. From the Massachusetts Institute of Technology.
Dr. Anna Balazs – Synthetic Robot Skin
When we press on something, our skin takes that touch as a mechanical impact and translates it into a chemical signal. This is how the brain is able to perceive objects through the sense of touch. There are few synthetic materials that can produce a chemical signal in response to mechanical stimuli and thus, act as an effective artificial “skin.”
Through mathematical modeling, my research group and I predicted that polymer gels undergoing a specific chemical reaction known as the Belousov-Zhabotinsky reaction—or BZ for short—could potentially be driven to send out a chemical signal when pressed. To us, these materials seemed ideal. That’s because the BZ reaction can drive the gel to expand and contract rhythmically. While in a petri dish, the gel literally pulsates like a heart. Under certain conditions, however, the gels do not move, or oscillate. We wondered: if a mechanical stimulus could be used to resuscitate the BZ gel “heart”?
Team members Krystyn Van Vliet and Irene Chen performed experiments showing that, by applying a critical pressure to the sample, the non-pulsating BZ gels could indeed be “resuscitated.” To illustrate this, we cut three separate BZ gel pieces, which resembled a smile and two eyes. What resulted was uncanny. Initially, these pieces did not pulsate, but when pressed, the smile not only oscillated, but also sent out a chemical signal indicating that it had been touched which allowed the nearby gel eyes to oscillate and appear to blink.
These mechanically activated, chemically reactive gels can be used to design touch-sensitive sensors. Ultimately, they could form a layer of skin for robotics applications, allowing robots to feel mechanical pressure in a way that mimics the human sense of touch.