The idea of liquid metal that can harden into any shapes, like that of a man or whatever else, is an old one, predating science fiction films, but it never went part the stage of imagination. Now it has, though, and it's all thanks to 3D printing.
Well, not exactly. Scientists have been trying to come up with self-assembling robots for many years, decades even.
Fluid parts have always been one level of difficulty above that, but they have, nonetheless, been on the minds of many engineers.
3D printing technology was just the last puzzle piece, the catalyst in a way, because it provided them with an idea: to use a concept similar to fused deposition modeling, where items are made drop by drop.
Case in point, a team of researchers from Tsinghua University and the Chinese Academy of Sciences have created liquid metals that can be manipulated with electrical charges.
The team was led by Lei Sheng, Jie Zhang, and Jing Liu of the Department of Biomedical Engineering, School of Medicine at Tsinghua in Beijing.
The “robots” are small enough to be useless, sadly, about as big as water droplets, but at least they've proved the ability to fuse together into various shapes and swirling combos.
There are spheres, concave lenses (not that they are transparent to work as such), interconnected balls (droplets really), etc.
Eventually, the scientists hope to lead to the creation of large and complex things, although one has to wonder how much energy will need to run through the metal at every given moment.
The method also suggests that a network of wires will need to be spread through whatever object the liquid metal is used to create, not to mention that the materials harden once cooled.
This means that true free-form liquid metal items and bodies will not be possible unless the team finds another way to deliver the electrical charge. Perhaps through some of the metal droplets themselves, somehow.
"A 'smart liquid metal machine' could be extended to three dimensions when a spatial electrode configuration is adopted," says Liu.
The new liquid metal used to achieve the breakthrough (called Liquidmetal) is actually a set of alloys based off zirconium. The materials they combine into have high tensile strength, corrosion resistance and anti-wearing characteristics, and are three times tougher than stainless steel once cooled.
Still, they have been successful in creating 3D modeling units, however small, which have melting points at room temperature when submerged in water. So far, they've "self-assembled" a single sheet of liquid metal film and turned it into a sphere (took separate metal droplets and joined them to create "controlled self-rotation and planar locomotion" of the droplets) or swirls (by causing vortexes in the surrounding water).