T-1000 prototype, a shapeshifting robot made from liquid metal that can take the form of everything it touches as presented in "Terminator 2" is not so far from reality as it seems.

Researchers from the Technical Institute of Physics and Chemistry at the Chinese Academy of Sciences and the medical school of Tsinghua University made a liquid metal droplets that are able to move along the path full of obstacles by "eating" aluminum particles in order to propel themselves. The finding, which may pave the way for the development of a liquid metal robot, was published in the Advanced Materials journal. These so-called self powered liquid motors can also change shape, allowing them to get through narrow spaces.

For their experiment, Chinese experts who designed these machines have used a mixture of gallium, indium and tin, which are immersed in a solution of sodium hydroxide. Salt water can also be used as a substitute for this solution.

At a temperature of 29°C gallium is in liquid state, while indium has a higher melting point (156°C).
However, when combined at room temperature the mixture is a liquid and has a high surface tension of 500 mN/m. This means that when this mixture is placed on a flat surface, it forms almost a perfect sphere, which is able to maintain its shape. When the aluminum is placed in the solution, it causes reaction due to which a hydrogen bubbles are created. These bubbles support the movement of the droplets, which means that they have the function of fuel. Such a propellant is even sufficient to allow the droplets to move "up the hill". The difference in pressure at the front and rear of the droplet is exactly what allows it to move.

This technique can be used for the control of the movement of liquid metal. The aforementioned technique could probably be applied to other materials as well. However, only liquid metal is studied so far.

As a result of further tests, droplets that would be able to transfer materials through the tubes or even deliver drugs through the blood vessels could be created.

This research is part of a project that aims to create adaptable robots that can change its shape, as the development of advanced shape-shifting flexible intelligent machines is a dream shared by scientists and engineers.