If you see gamers poking at their forearms to play Angry Birds on the bus in the year 2020, remember when you first heard this would happen. South Korean researchers have developed a clear plastic touchpad that works even when it’s stretched to more than 10 times its normal area.
The touchpad is made of hydrogel – a type of flexible, stretchable substance that’s also used in soft contact lenses, diapers and medical devices. For the experiment described in this week’s issue of the journal Science, the researchers added lithium chloride salts to make the hydrogel electrically conductive.
Electrodes on each end of the touchpad create an electrostatic field across the hydrogel sheet. When you press your finger onto the pad, it closes an electrical circuit and creates a current that can be read by meters on each corner of the sheet.