Reprogrammable Magnetic Soft Robots Based on Low Melting Alloys

Magnetic soft robots featuring untethered actuation and high mechanical compliance have promising applications ranging from bionics to biomedicine. However, their fixed magnetization profiles pose a challenge for adaptive shape transformation in unpredictable environments and dynamic tasks. Herein, a reprogrammable magnetic soft composite is reported by encapsulating magnetic neodymium-iron-boron microparticles with low melting alloy (LMA) and embedding them into the elastomer. Utilizing the phase transition of the LMA, the magnetic microparticles can be reoriented under an external magnetic field and they can be immobilized through LMA solidification, allowing the robot to obtain a new magnetization profile corresponding to its temporary shape. By changing the LMA composition, the robot with multiple programming temperatures can be fabricated and its local magnetization profiles can be selectively programmed in different temperature ranges. A bioinspired crawler with multimode locomotion, a reconfigurable robotic gripper capable of adaptable grasping, and reconfigurable electronic circuits are also demonstrated. This work may pave the way for the next-generation magnetic soft robots and reconfigurable devices.