For well over a decade, scientists have known about a class of polymers that would react to and move toward light with no other power source.
While certainly fascinating, the technology was limited in its application in the real world, because the movement was so slow.
“So we asked ourselves, can we make these materials move faster and increase the mechanical power that they generate?”
Posing the question is M. Ravi Shankar, an associate professor of industrial engineering at the University of Pittsburgh. For the better part of a year, he’s been tackling this problem with Timothy J. White and Matthew Smith, who both work at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Dayton, Ohio.
Now, they think they’ve got it.
“As we were examining different approaches, we thought why not borrow from the idea that helps the Venus flytrap and the hummingbird’s beak snap up prey?” Shankar said.
Using the polymer, the scientists essentially built a structure that looked and worked like the hummingbird’s beak and the flytrap’s trap.
“So the idea is that once we created this geometry from the photo-responsive polymer, we irradiated it with light,” Shankar said. “It initially deforms slowly, but when it reaches a critical state, it essentially snaps.”
The snapping mechanism essentially turns the polymer into a binary switch, and this, Shankar said, is where the possibilities for real-world application lie.
Shankar said it may be possible to build structures out of the switches, controlling the movement of each part of the structure with a dedicated light source.
“Can we create morphing structures?” asked Shankar. “Let’s say, a robotic arm that is steered and powered only with light. Or we can think of something like a light-driven transformer, like Optimus Prime but that’s driven by light and nothing else.”
Shankar said, in the future, scientists may be able to develop a whole class of photo-mechanical machines.
The most fascinating part, according to Shankar, is that the polymers themselves need no other power source to generate the movement. The light itself powers the movement.
Shankar, White, and Smith published their findings in the Early Edition of the Proceedings of the National Academy of Sciences, which was released in early November.