Magnetoactive phase transitional matter (MPTM) are miniature robotic machines that can change their shape by switching between liquid and solid state.[1]
MPTMs consist of liquid metal embedded with a neodymium magnet.[1] MPTMs can be programmed to change shape when needed, by using heating and ambient cooling.[1] Heat is generated from an incorporated heating element, or by use of magnetic pulses, switching the robot into liquid mode.[1] Ambient temperatures provides cooling to change the robot into a solid state.[1] The magnetism of the metal holds the machine together while in liquid mode.[1]
MPTMs were first created by a collaboration of scientists from Sun Yat-sen University, Carnegie Mellon University, Chinese University of Hong Kong, and Zhejiang University.[2][3] Their robot incorporated a heating element, and was able to melt itself to change shape.[3] The first MPTM incorporated neodymium, iron, and boron microparticles in gallium and had a melting point of 29.8 °C.[2][4]
A January 2023 academic paper demonstrated the potential to use MPTMs for mechanical assembly in hard to reach locations, and in medical procedures.[1] Medical use cases were delivery of drugs in the human stomach and the removal of foreign objects.[1]