Oscillating gel acts like artificial skin, giving robots potential ability to 'feel'

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, Anna Balazs, Distinguished Professor of Chemical and Petroleum Engineering in Pitt's Swanson School of Engineering, 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.

"Think of it like human skin, which can provide signals to the brain that something on the body is deformed or hurt," says Balazs. "This gel has numerous far-reaching applications, such as artificial skin that could be sensory—a holy grail in robotics."

Balazs says the gel could serve as a small-scale pressure sensor for different vehicles or instruments to see whether they'd been bumped, providing diagnostics for the impact on surfaces. This sort of development—and materials like BZ gel—are things Balazs has been interested in since childhood.

"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."

Also on Balazs's research team were Olga Kuksenok, research associate professor, and Victor Yashin, visiting research assistant professor, both in Pitt's Swanson School of Engineering. At MIT, the work was performed by Krystyn Van Vliet, Paul M. Cook Career Development Associate Professor of Material Sciences and Engineering, and graduate student Irene Chen.

Provided by University of Pittsburgh

New technology expands ability to recycle precious metals

Precious metals like platinum and rhodium are very valuable, and also very rare. That makes it increasingly important to recycle these precious metals from a wide variety of industrial uses. For example, various catalytic processes in the chemical industry generate large amounts of fluid residue containing low concentrations of precious metal catalysts.

The new adsorption process (scavenger technology) being offered in cooperation with the PhosphonicS company in the UK will allow Heraeus to reprocess waste solutions that contain even low concentrations of precious metals. Up until now, it simply was not affordable or profitable to recycle them.

“This strategic partnership is another building block for us to offer our customers a broader range of precious metal recycling,” notes Dr. Joachim Kralik, Head of Chemical Process Development Recycling in the Heraeus Precious Metals Business Unit. Heraeus brings to the partnership its wide-ranging expertise with precious metals and many years of experience in recycling materials containing precious metals—especially from industrial catalysts. This cooperation means that Heraeus customers from the pharmaceutical, industrial, and specialty chemical industries will be able to optimize their processes, both ecologically and economically.

Together with PhosphonicS, Heraeus offers a wide range of a new generation of select and efficient adsorption agents—called scavengers—to remove and recover precious metals from chemical products and waste solutions. Since this can accomplish precious metal output levels for process solutions in the single-digit ppm range (ppm = parts per million), even the slightest amounts of precious metal are retained and reused in the precious metals cycle, saving both resources and the environment.

The scavenger process allows the efficient recovery, even for waste solutions with extremely low concentrations of precious metals. “With this process, it’s almost like we’re pulling finely distributed precious metal residue from the solution with a ‘chemical magnet.’ The precious metal is bound to the surface of the adsorption medium. We can reprocess that material with its valuable content using wet-chemical processes in a way that yields pure precious metal,” explains Dr. Kralik in simple terms.

In principle, the scavenger process can be used for all precious metals. This technology has already been successfully employed for heavily-diluted organic platinum and rhodium solutions from homogeneous catalytic processes from the chemical industry. Rhodium is principally needed for catalytic converters for the automotive industry, but also finds widespread application in the chemical industry because of its outstanding catalytic properties. Homogeneous catalytic processes using rhodium play an important role in the production of special chemicals (plasticizers, acetic acid, acetic anhydride, and pharmaceutical agents). Platinum catalysts are important for silicone production.