Terminator-style robot brought to life in lab
Scientists create liquid metal shape-shifting figure able to melt through bars and reform in minutes
WHEN a desperate Sarah Connor flees an asylum in the film Terminator 2, the chasing cyborg passes through metal bars by melting and reforming.
Now scientists in the United States have made the closest thing yet to the fictional T-1000 by making a shapeshifting robot.
They took the humble sea cucumber as their inspiration to design miniature robots that rapidly and reversibly shift between liquid and solid states.
Experts from Carnegie Mellon University in Pittsburgh took gallium, a metal that melts at room temperature, and enriched it with magnetic particles. Gallium, combined with ferromagnetic neodymium-iron-boron particles, melts at 30.6C (87.08F) and when an alternating magnetic field was sent through the material, which was shaped like a miniature Lego figurine, its temperature increased, allowing it to melt.
Now a puddle, the magnetic field was able to move the melted metal man from within a cage to an area outside, where it was gathered in a mould, reformed and left to cool down after the magnetic field was turned off.
With its temperature back below 30C – in line with ambient room temperature – the robot regained its strength and original shape within 80 seconds of the field being switched off.
“The magnetic particles here have two roles,” said Dr Carmel Majidi, a senior author and mechanical engineer at the university.
“One is that they make the material responsive to an alternating magnetic field, so you can, through induction, heat up the material and cause the phase change.
“But the magnetic particles also give the robots mobility and the ability to move in response to the magnetic field.”
Scientists say previous attempts to make shape-shifting robots have needed heat guns, electrical currents or other external heat sources to control the shift from solid to liquid states.
But by enriching gallium with magnetic particles, and ensuring the work is carried out in a strictly temperature- controlled room, a magnetic field is all that is needed.
In their study, published in the journal Matter, the team writes that when in a solid state the material has impressive tensile and compressive strength and can hold heavy weights.
But when in a liquid state it is also more fluid and less viscous than other attempts at making a shape-shifting robot owing to the properties of the gallium-enriched compound.
“This unique combination of properties is enabled by the reversible transition between rigid and fluidic states through alternating magnetic field heating and ambient cooling,” the scientists write.
In their experiments the researchers were able to use magnetic fields to manipulate the metal and make it jump, climb walls, and split in half to move other objects. The team said the material could be used in a host of robotics applications such as fixing hard-toreach circuits, acting like a universal screw and to help clear blockages in the body or deliver drugs.
“Now we’re pushing this material system in more practical ways to solve some very specific medical and engineering problems,” said Chengfeng Pan, an engineer at the Chinese University of Hong Kong who led the study.
“Future work should further explore how these robots could be used within a biomedical context,” said Dr Majidi.
“What we’re showing are just one-off demonstrations, proofs of concept, but much more study will be required to delve into how this could actually be used for drug delivery or for removing foreign objects.”