The future could belong to robot octopuses: soft, flexible, durable, with displays written across their super-stretchy skin. Scientists at Cornell University have just taken the first step toward such robot with a light-up flexible skin that stretches to nearly six times its original size, splitting the difference between skin and screen.
In a new paper in Science, Chris Larson and Bryan Peele describe a flexible membrane that can light up in different colors as it’s stretched. Previous skins could be stretched to about 120 percent. This new skin can maintain its display while being stretched 480 percent, four times more than any previous luminescent “skin.” It can be twisted, poked, and rolled up, and the scientists hope that someday we can wear it like sleeves or even cover entire robots with it—preferably robot octopuses.
In the field of soft robotics, an octopus is the gold standard. It can twist and bend itself into nearly any shape, shrink down and expand, and manipulate objects with delicacy while retaining its strength.
That ideal is pretty far in the future. So far, Larson and Peele have made a robotic inch worm. The design isn’t meant to show off motion, but to demonstrate its incredible skin.
Hydrogel layers on either side conduct electricity. Sandwiched between the layers of hydrogel is a layer of silicone with embedded phosphors, which light up when electricity moves through them. Different metals emit different wavelengths of light, so a bit of copper will make blue light, while magnesium will emit yellow light.
The inch worm bot doesn’t look impressive at first, because it seems as though the chambers inside its three segments are being lit up. They’re not. The skin itself is what’s giving off light as it’s stretching and moving. If it were pulled or wrapped around a wrist, it would do the same.
That’s something Larson specifically wants to do with soft robotics. Right now, we’re trying to shrink rigid displays so they can be held flat against small parts of our bodies—like watches on our wrists or phones in our pockets. Larson hopes for a future in which we don’t have an Apple watch, but rather an Apple sleeve. Instead of engineering smaller laptops and phones, we could engineer flexible screens that we could carry around in a pocket but that would stretch up to the size of a softball.
Beyond that, the researchers are hoping to cover entire robots with this skin, largely to make them more approachable for humans. “A lot of communication is visual,” Peele explained. Giving a robot a soft skin that can light up with a display, or even a face, gives it a “mechanism of expression.”
But robot medical assistants, full-sleeve computers, and stretch-screens are still well into the future. Right now researchers are working on ways to improve their design. Their current production methods are basic—a way to show that this stretchable skin is achievable. The large pixels on the inch worm and flat skin can, they think, be shrunk down to be comparable to pixel size on a regular computer.