A simple metal compound could make some big waves in robotics thanks to a strange property. It can move under its own volition, given the right environment. It's also in a liquid state, meaning it can change shape to negotiate bends and curves.

LIU Jing and his colleagues at the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences and Tsinghua University, have discovered a 'smart' liquid metal alloy that moves on its own. The liquid metal is a mixture of gallium, indium and tin. It stays liquid at temperatures above -2 degrees Fahrenheit (-19 Celsius), can move itself in a circle, straight line, or even squeeze through complex shapes when placed in a sodium hydroxide solution.

Its integrated power source is a flake of aluminum embed in the liquid metal. The aluminum reacts with the sodium hydroxide to release hydrogen gas, while placing the aluminum in the liquid metal drop's rear creates differences in electrical charges across the liquid metal. The charge differences in differing parts of the liquid metal causes movement, as the liquid metal physically adjusts itself to balance out the resulting differences in internal pressure. Currently, a drop of liquid metal has enough power to move around for 30 minutes to an hour. Nanotechnology could be used to build the embedded control system, sensors and computers for any liquid metal robot.

It might be basic research now, but self healing metals would have a lot of applications.

Scientists believe they can use electrical currents to control multiple droplets at the same time. The team has published their findings in the journal Advanced Materials.

Liquid metal motor moves by itself (Image by LIU Jing)