Robot liquify to escape from a cell, then solidify on the other side


Scientists have created a tiny "Terminator 2"-like robot that can melt and resolidify itself on command, enabling it to easily escape from confined spaces.

To make the phase-shifting robot, scientists embedded microscopic chunks of magnetic neodymium, boron and iron into liquid gallium (a metal with a low melting point) and left it to solidify.

And just like the spine-chilling T-1000 from "Terminator 2," the robot has shape-shifting abilities that make it an excellent escape artist. By using magnets to command their miniature creation to melt, the researchers recorded the robot transforming into an amorphous puddle to slither through the bars of a cage before miraculously reconstituting itself on the other side. The researchers published their findings Jan 25 in the journal Matter.

"The magnetic particles here have two roles," senior author Carmel Majidi, a mechanical engineer at Carnegie Mellon University, said in a statement. "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."

The researchers said the inspiration for the device came from sea cucumbers, which have been observed switching between soft and stiff states to protect themselves from their environment and increase the weight they can carry.

The researchers see several potential medical and technological applications for their robot. So far, it has passed multiple tests: fixing circuits by entering tough-to-reach spots and then transforming itself into solder; melting into a screw socket and then solidifying to become a mechanical screw; and removing a foreign object from a model stomach.

"Giving robots the ability to switch between liquid and solid states endows them with more functionality," lead author Chengfeng Pan, an engineer at The Chinese University of Hong Kong, said in the statement. "Now, we're pushing this material system in more practical ways to solve some very specific medical and engineering problems."


JOURNAL Matter - DOI 10.1016/j.matt.2022.12.003