Video Measuring just 60 microns across – about the width of a single strand of human hair – the world’s smallest self-folding origami bird is a feat of engineering.
All it takes is a zap of positive voltage to get the tiny sheet of atoms to automatically curl up into a bird-like shape in 100 milliseconds. It’ll continue to hold its shape, without any outside power needed, until a jolt of negative voltage flattens it out again.
“One thing that’s quite remarkable is that these little tiny layers are only about 30 atoms thick, compared to a sheet of paper, which might be 100,000 atoms thick,” said Paul McEuen, a physics professor at Cornell University, who took part in the experiment. According to the US college, this is how it works:
The devices consist of a nanometer-thin layer of platinum capped with a titanium or titanium dioxide film. Several rigid panels of silicon dioxide glass sit atop those layers. When a positive voltage is applied to the actuators, oxygen atoms are driven into the platinum and swap places with platinum atoms. This process, called oxidation, causes the platinum to expand on one side in the seams between the inert glass panels, which bends the structure into its predesignated shape.
The glass panels can be altered to shape the device into its final form as needed. Here’s a video of it in action:
Although the teeny bird doesn’t really do much other than self-fold at the moment, its masterminds – who have published a paper about their work in Science Robotics – believe it’s a step toward making tiny machines that could one day remove bacteria or perform surgery.
“In part we are interested in the fundamental science of how does one design, build, and operate machines at this scale,” Itai Cohen, a physics professor at Cornell and co-author of the paper, told The Register.
What new worlds will we be able to explore when we can interact with the world on a scale comparable to simple cell-sized organisms?
“There is a huge amount to learn here from just a pure science perspective. From a practical point of view, just think of everything robots do for us at the macroscale. Could we shrink robots with that degree of functionality down to the microscale? Could we have the equivalent of a roomba sweeping a surface removing bacteria instead of dust, or microsurgery robots shrinking our surgeon’s precision by an order of magnitude? What new worlds will we be able to explore when we can interact with the world on a scale comparable to simple cell-sized organisms?”
But before the team gets to that point, it needs to figure out how to attach controller chips to the tiny foldable robots. We're told it will be possible to drive the actuator using CMOS transistors, the kind found on chips, which is a good start.
With suitable microcontrollers fitted, the robots can be programmed to detect and react to different molecules or light, or have the ability to communicate with other robots, Cohen told us.
“We humans, our defining characteristic is we’ve learned how to build complex systems and machines at human scales, and at enormous scales as well,” added McEuen. “But what we haven't learned how to do is build machines at tiny scales. And this is a step in that basic, fundamental evolution in what humans can do, of learning how to construct machines that are as small as cells.”
The boffins behind their work are also in the Guiness Book of Records for building the smallest robot capable of walking. ®