A group of Korean materials scientists at the National University of Seoul, led by Chong-Chan Kim, had just developed an “ionic”, translucent, jelly-like computer touchpad that can be worn on the wrist and used just like a regular smartphone screen to scroll, click, drag, swipe, play video games and even type words.
According to Kim, the screen remains fully functional even when stretched to 1,000 percent of its areal strain. “The versatility comes from the material that we have used,” says Jeong-Yun Sun, one of the scientists behind the new invention. The touchpad is made from a fascinating combination of hydrogels, which you can think of as almost a gelatinized plastic. “Hydrogels are soft, transparent, and bio-compatible,” Sun says.
A highly conductive material, called lithium chloride salts (LiCL), contained within the polyacrylamide hydrogel allows current to zip through the area of the screen as if it were a spongy copper wire. Once the pad is touched, a computer attached to the controller board of the panel calculates the exact location of your fingertip by detecting a resulting electricity spike and relating that spot to all four of the pad’s corners which supply the current. Regardless of how much the screen is stretched beyond its normal state, the basic science remains the same.
In a series of tests, Sun and colleagues found their new invention to be perfectly usable for a wide range of video games, playing a virtual piano keyboard, and writing.
Before commercialization (which the team hopes “will be coming soon”) becomes viable, one key issue has to be resolved first, and that is – how to prevent the hydrogel from drying over time. While the novelty of wearing a bendy touchscreen on the wrist is definitely exciting, having it decay like a piece of old rubber would likely kill much of the joy fairly quickly.
To address that, Sun and his other three comrades will have to find a way to encapsulate the pad in a thin film to keep it out of direct contact with the outside environment.
A report on the invention has just been released in the leading academic journal Science.