Robots can solve puzzles, assist with surgery, and even stand in for caregivers, but ask one to handle potato chips without crushing them and humans still prevail. Robotic hands just aren't sensitive enough. A new material dubbed "frozen smoke" could be the skin they need for a lighter touch.
"It's a kind of very light carbon nanotube material," said Lei Zhai, the associate professor of chemistry at the University of Central Florida who led the material's development. Zhai and his team created the aerogel by fusing the tubes together in a novel way.
Carbon nanotubes have advantages: they're strong, conductive, and have large surface areas. But their high aspect ratio means they naturally form bundles. Zhai compares them to fused chopsticks. "In order to use them, you have to separate them."
The UCF approach separates the carbon nanotubes while retaining their useful properties. The resulting "frozen smoke" aerogel is flexible and has conductivity that makes it an ideal sensor. According to Zhai, the material is sensitive enough to detect one pascal of pressure. He said he envisions using that sensitive pressure for robotic surgery.
Currently, very small robotic hands can hold tools, reach inside a patient's body, and excise tissue, Zhai explained. However, controlling how deep and hard to cut is difficult.
"Right now all the pressure-sensing devices, they can sense very heavy or large pressure so they cannot [perform] delicate or complicated surgery," he said. A thin film of the aerogel on a robotic hand could serve as a kind of skin.
The material's large surface area, flexibility, low density, and high conductivity also make it compelling for energy storage. The scientists think it could lead to more efficient batteries and super capacitors. Zhai's team recently published an article about the aerogel in ACS Nano.
Zhai said that he and his colleagues are now looking for industry partners. He added that they are working with specialists at the university's NanoScience Technology Center on robotic applications to help patients with tasks such as opening a bottle of water.
Chris Li, an associate professor of materials science and engineering at Drexel University, specializes in nanotube assembly structures. He said that Zhai's material has an elegant design.
"Nanotubes have also been used in all kinds of bio-sensing. You can conceive of this as a smart scaffold," he said of the aerogel. "I hope that by using even smaller tubes they can push to a larger surface area and more sensing applications. The concept is quite novel."
Zhai said the material has applications beyond surgical robotics, chemical detection, and energy storage. "Have you watched the movie 'Mission Impossible?'" he asked. Referencing the unbelievably responsive series of sensors the protagonists must trick to infiltrate CIA headquarters, he said, "It's pretty much like that."