A metal alloy that powers its own movement and deforms to get through tight spots could let us to build a Terminator 2 style robot (minus homicidal tendencies)
Hasta la vista, baby. A real-life T-1000
, the shape-shifting liquid-metal robot from Terminator 2
, is a step closer, thanks to a self-powered liquid metal motor.
The device is surprisingly simple: just a drop of metal alloy made mostly of gallium - which is liquid at just under 30 °C - with some indium and tin mixed in. When placed in a solution of sodium hydroxide, or even brine, and kept in contact with a flake of aluminium for "fuel", it moves around for about an hour. It can travel in a straight line, run around the outside of a circular dish, or squeeze through complex shapes.
"The soft machine looks rather intelligent and [can] deform itself according to the space it voyages in, just like [the] Terminator does from the science-fiction film," says Jing Liu from Tsinghua University in Beijing, China. "These unusual behaviours perfectly resemble the living organisms in nature," he says, adding that they raise questions about the definition of life
When they first saw the drop move, Liu and colleagues weren't sure how it was able to do so. Experiments revealed two mechanisms at play. Some of the thrust stems from a charge imbalance across the drop, which in turn creates a pressure differential between the front and the back that pushes it forward. The aluminium also reacts with the sodium hydroxide, releasing hydrogen bubbles which drive the drop even faster.