A Review of Magnetic Elastomers from Material Design and Fabrication Methods to Applications in Soft Robots

Abstract

Magnetic elastomers (MEs) are a novel class of smart materials defined by their rapid and reversible mechanical property modulation under external magnetic fields. These unique functionalities of MEs empower the essential advantages for advanced magnetic soft robots to achieve untethered operation, complex shape morphing, and adaptive stiffness control in practical potential applications, such as minimally invasive surgery and confined-space exploration. However, although numerous reviews have examined MEs from various disciplinary viewpoints, a significant gap remains in systematically correlating how key aspects such as material selection and fabrication methods collectively influence the functional performance and real-world applicability of magnetic soft robots. Therefore, this review systematically examines MEs from the perspective of soft robotics applications, structuring the discussion around the critical interplay among material design, fabrication methods, and functional performance. It begins by analyzing material compositions─focusing on the selection of magnetic fillers and polymer matrices─and connects their intrinsic properties directly to the actuation, sensing, and stiffness modulation requirements of soft robots. Subsequently, the review categorizes and assesses advanced fabrication strategies, emphasizing their role in achieving complex architectures and programmable magnetization patterns essential for robotic functionalities. Finally, this review demonstrates the functional application of MEs across soft robots, showcasing how material and manufacturing capabilities translate into real-world performance in untethered actuation, intelligent sensing, and adaptive stiffness control. By synthesizing current research within this application-oriented framework, this review aims to provide a clear roadmap for the development of high-performance, magnetoelastic, soft robots.