An easier way to create printed circuits on paper using a liquid metal ink

These lines of liquid metal have been printed onto paper using a customised desktop printer. The team behind the technology say it may one day be possible for people to print their own electronic devices at home.

Flexible electronics are gaining popularity, and the idea of using paper that can easily be bent or folded has been around for a while. But the equipment and conditions needed to print liquid metals onto paper rule out easy, large-scale production.

Now, a team led by Jing Liu of the Chinese Academy of Sciences has found a way to print flexible circuits at room temperature. They used commercially available paper and equipment, with a few modifications, such as adding a brush-like porous tip to the dispensing nozzle to prevent the ink clogging. The ink itself is a gallium–indium alloy, which stays liquid at room temperature, and is coated with silicone after printing. The resulting electronics work well and can be bent without breaking.