Researchers at Carnegie Mellon University, in the United States, have developed a robot capable of switching between solid and liquid state as if it were a T-1000 — the villain of the second film in the Terminator franchise, by James Cameron — made of liquid metal.
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According to the scientists, far from science fiction movies, this miniature robot has properties that are much more useful than crossing the bars of a prison, and can be used in medicine or in other applications, including inside the human body.
“Our robot is nothing more than a magnetoactive solid-liquid phase transition machine that incorporates magnetic particles of gallium, a metal with a melting point well below 29.8 °C”, explains professor of mechanical engineering Carmel Majidi, main author of the study.
Escaping from the “prison”
In one of the videos released by Professor Majidi’s team, it is possible to see the robot escaping from a miniature prison, simply passing through the bars. To do this, the bot goes from a solid state to a liquid state and then returns to its solid form outside the cell.
This ability to switch between solid and liquid state occurs thanks to the use of a metallic matrix of gallium together with particles of an alloy containing three other elements — neodymium, iron and boron — that help to amplify the device’s response to magnetic fields.
“The magnetic particles here have two functions. One is that they make the material more responsive to an alternating field, so you can, by induction, heat the material and cause it to change phase. On the other hand, they also give robots mobility and the ability to move according to the magnetic field”, adds Majidi.
The little robot used during lab tests is the size and appearance of a LEGO figure. Approximately five millimeters wide and one centimeter tall, scientists used a magnetic field to melt it and pull it out from behind bars.
In addition to the ability to melt material, these magnetic fields allow the robot to jump 20 times its own height, spin around at 1,500 rotations per minute or manage to move at an impressive speed of approximately one meter per second.
“In the future, this robot could be used, for example, to move foreign objects inside the stomach, or as a medication delivery system. We also demonstrated that the bot can repair circuits, leaking into hard-to-reach areas and acting like a solder, or like a screw that occupies a hole in its liquid form, sealing it after it solidifies”, concludes Majidi.