Kyung Hee University Develops Magnetically Responsive Intelligent Material

by Choi Youngchan

Pubilshed 04 Sep.2025 15:01(KST)

Development of a New Material That Can Autonomously Change Its Properties
Magnetically Programmable Metamaterial Achieves Precise, Real-Time Stiffness Control
Inspired by Muscle Structure, Enables Rapid Transition Between Soft and Rigid States
Published in Advanced Materials, Demonstrates Potential for Intelligent Wheel Systems

Kyung Hee University announced on September 4 that a research team led by Research Professor Park Yunseok from the Department of Advanced Materials Engineering, along with researcher Jung Guyoon, in collaboration with Dr. Seol Seungkwon’s team at the Korea Electrotechnology Research Institute (KERI), has developed a mechanical metamaterial that enables precise real-time control of stiffness using magnetic fields.

Research Schematic. Utilizing magnetic fields to program three stages of stiffness in three dimensions, enabling fast and precise real-time control of a wide range of stiffness. Kyung Hee University

This achievement was published on August 28 in the world-renowned journal in materials science, Advanced Materials.

Recently, there has been a growing demand in next-generation industries for intelligent materials that can autonomously alter their physical and chemical properties. However, conventional materials have fixed properties, which limits their flexibility and the realization of precise functions.

To address this, the research team was inspired by the structure and operating principle of the sarcomere, the basic unit of muscle contraction, and developed a metamaterial that can rapidly transition from a soft and flexible state to a hard and rigid state in response to external magnetic fields.

The developed metamaterial enables ternary programming of stiffness-soft, intermediate, and hard-allowing for greater precision and faster response compared to conventional binary (on/off) systems.

In this study, the team used a 4D printing method to fabricate structures with an ink composed of neodymium magnetic particles (NdFeB) and a highly elastic polymer, Styrene-Isoprene-Styrene (SIS).

The resulting magnetically tunable stiffness metamaterial (MTSM) responds to magnetic fields in approximately 0.1 seconds and achieves a stiffness tuning range of over 390%. Furthermore, when extended to a three-dimensional array, it can control multiple layers of stiffness modes depending on the direction and strength of the magnetic field.

To demonstrate practical applications, the research team showcased an "intelligent wheel system" whose stiffness changes in response to magnetic fields. The wheel deformed softly to overcome obstacles on rough terrain and maintained rigidity for stable operation on flat surfaces.

Professor Park stated, "This research serves as a stepping stone toward true 'intelligent materials' that can autonomously program their mechanical properties in response to external stimuli, beyond simple deformable materials."