By Mary Fetzer
Someone taps your shoulder. The organized touch receptors in your skin send a message to your brain, which processes the information and directs you to look left, in the direction of the tap. Now, Penn State and U.S. Air Force researchers have harnessed this processing of mechanical information and integrated it into engineered materials that ‘think.’
The work, published in August in Nature, hinges on a novel, reconfigurable alternative to integrated circuits. Integrated circuits are typically composed of multiple electronic components housed on a single semiconductor material, usually silicon, and they run all types of modern electronics, including phones, cars and robots. Integrated circuits are scientists’ realization of information processing similar to the brain’s role in the human body. According to principal investigator Ryan Harne, James F. Will Career Development Associate Professor of Mechanical Engineering at Penn State, integrated circuits are the core constituent needed for scalable computing of signals and information but have never before been realized by scientists in any composition other than silicon semiconductors.
His team’s discovery revealed the opportunity for nearly any material around us to act like its own integrated circuit: being able to ‘think’ about what’s happening around it.
“We have created the first example of an engineering material that can simultaneously sense, think and act upon mechanical stress without requiring additional circuits to process such signals,” Harne said. “The soft polymer material acts like a brain that can receive digital strings of information that are then processed, resulting in new sequences of digital information that can control reactions.”
The soft, conductive mechanical material contains reconfigurable circuits that can realize combinational logic: when the material receives external stimuli, it translates the input into electrical information that is then processed to create output signals. The material could use mechanical force to compute complex arithmetic, as Harne and his team demonstrated, or detect radio frequencies to communicate specific light signals, among other potential translation examples. The possibilities are expansive, Harne said, because integrated circuits can be programmed to do so much.
According to Harne, the material uses a similar ‘thinking’ process as humans and has potential applications in autonomous search and rescue systems, in infrastructure repairs and even in bio-hybrid materials that can identify, isolate and neutralize airborne pathogens.
“What makes humans smart is our means to observe and think about information we receive through our senses, reflecting on the relationship between that information and how we can react,” Harne said.
AR Issue #130
Impossible Material Ushers in the Graphene Age
by Jeanne Manning
