A team of Chinese and American researchers has built a robot that can switch between solid and liquid states.
Researchers from Sun Yat-sen University, the Chinese University of Hong Kong, Zhejiang University, and Carnegie Mellon University say the invention could be useful in medicine and microelectronics.
In a video released by the team, a small robot “prisoner” melts into a liquid and slips out of a closed cage. To create the shapeshifter, the scientists developed a non-toxic material based on gallium, a metal with a low melting point of about 29.8 °C. To make the magneto-active phase transition material (MPTM), the team embedded magnetic microparticles into the gallium. Under an alternating magnetic field, a robot made from that material could switch between states of matter, explained Dr. Carmel Majidi, the study’s lead author at Carnegie Mellon University.
According to Majidi, the magnetic microparticles make the MPTM respond to a changing magnetic field. The material heats by induction and undergoes a phase change, Sci.news reports.
The scheme and application of the liquid-solid phase transition MPTM.
Image author: Wang et al., doi: 10.1016/j.matt.2022.12.003.
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Interestingly, the inventors didn’t model the robot on a movie character famous for changing its state of matter. They looked to real animals that can switch from soft to hard, like sea cucumbers.
Giving robots that ability adds remarkable functionality, says Chengfen Pan of the Chinese University of Hong Kong.
In tests the team examined the material’s mobility and strength under different conditions. The robots jumped over trenches, climbed walls, split in half to move an object, and then reassembled themselves. They also removed foreign objects from a stomach model and delivered medication to the same artificial stomach.
The robots were also tested as universal mechanical “screws” for assembling parts in hard-to-reach places. Finally, researchers used them to repair wireless circuits.
But Majidi says those demonstrations are one-off proofs of concept. Much more research will be needed to understand how this approach could be used for tasks like removing foreign objects.
