Liquid metal robots might be more than science fiction soon

It's as if all the pieces are falling in place to give birth to the SkyNet nightmare that haunts us in the Terminator universe: self-driving cars, a fleet of interconnected Internet-bearing satellites, and now, shape-shifting and self-propelling metal. This last one was a recent discovery of a group of researchers in Tsinghua University in Beijing, China, who stumbled upon a peculiar behavior of a certain mix of metals that, in the end, could change its shape to fit moulds and paths and propel itself forward as well.

The metal alloy is composed mostly of gallium kept liquid at around 30° C, with a mix of indium and tin. The alloy is placed inside a solution of sodium hydroxide, basically perhaps more known as lye. Ii is fed flakes of aluminum which it consumes and uses for fuel in order to move itself forward on paths, whether straight, bent, or curved, for about an hour.

It might sound like an excerpt or scene from science fiction, but it is pretty much simple science that, admittedly, remains fascinating. The aluminum flakes causes a charge imbalance in the drop of metal alloy, between its front and back sides, causing the drop to move forward. The aluminum also reacts with the lye solution that produces hydrogen bubbles, propelling the drop forward even faster.

But while this self-driving behavior is interesting in itself, the alloy has even more impressive properties. For one, if the drop is kept stationary, instead of moving, it can actually turn into a pump instead, using the same chemical imbalance to drive material away from it. Plus, the alloy can change shape to conform to the path it is traveling on, deforming and squeezing itself to fit narrower channels. And when you add an element of an electrical current, the gallium alloy can form complex and organic shapes, but then return to its drop form when the current is removed.

It is, of course, still a far cry from the self-aware killing machines of Terminator fiction, but we're slowly getting there. Minus the killing part, hopefully. While this unexpected discovery might seem whimsical and, at best, entertaining, the researchers are envisioning more practical uses, like in delivery materials or substances through pipes or even blood vessels.

VIA: New Scientist