Researchers have developed a ductile touchpad that can be worn on the arm and can be used to write words and play electronic games.
Scientists from Seoul National University in South Korea published their findings in the latest issue of the journal Science. While different types of conductors such as carbon nanotubes and metal nanowires have been explored for stretchy touchpads, they are all based on hard materials. To help solve this problem, Chong-Chan Kim and his colleagues developed a touchpad made of hydrogel, a network of hydrophilic polymers that are soft and highly stretchable.
They used a polyacrylamide hydrogel with added lithium chloride salts, which act as a conductor and help retain water in the hydrogel.
Electrodes on both ends of the hydrogel apply similar voltages that create a uniform electrostatic field throughout the system. When a finger touches the panel, the circuit in the hydrogel is closed, allowing the current to pass from both ends of the strip to the touch point.
The team also developed an on-board controller to facilitate communication between the ionic touch panel and a computer. With the help of the touchpad, they managed to draw a figure with the transmitted data on a computer screen.
The touchpad was able to function even after being stretched to more than 1.000 percent of its normal size, the researchers report.
Watch the video clip below to see how it works.
