Development of 'Self Smart Material' That Folds Like Paper on Its Own

Self-smart magnetic materials with changeable magnetic forms
Self paper folding possible according to magnetic field
Various applications expected in biomedical engineering, soft robotics, and more

[Asia Economy Reporter Junho Hwang] A technology has been developed that enables magnetic smart materials, which move autonomously in response to magnetic fields, to be realized in a wider variety of shapes. By utilizing this technology, the shape in which the material moves can be easily implemented and erased, making it expected to be applied in biomedical engineering, flexible electronic devices, soft robotics, and more.

The research teams led by Professor Jiyoon Kim from the Department of Materials Science and Engineering and Professor Minsang Kwon from the Department of Materials Science and Engineering at Seoul National University announced on the 3rd that they have developed a magnetic smart material with a changeable magnetization pattern, and their related paper was recently published in Nano Letters, an international journal in the field of nanotechnology.

The magnetization pattern is a blueprint that determines the strength of the magnetic force and the direction of the N-S poles. Depending on the magnetization pattern, the magnetic smart material exhibits properties such as bending or folding in specific directions.

Freely Controllable Magnetization Patterns

Structure and Principle of Magnetic Smart Materials with Self-Shape Redesign Capability

The research team developed a magnetic smart material whose magnetization pattern is not fixed. This material consists of micrometer-sized particles (magnetic microspheres) made by mixing magnetic particles (magnetic materials) and phase-change materials (PEG) embedded in a polymer matrix.

Because PEG is a phase-change material that transitions from solid to liquid, the magnetization pattern can be changed repeatedly. When the temperature rises, the phase-change material becomes liquid, allowing the magnetic particles to be reprogrammed with a new magnetization pattern using an external magnetic field. Conversely, when the temperature drops to room temperature, the phase-change material solidifies, physically immobilizing the magnetic particles and fixing the magnetization pattern.

Hyunseo Song, the first author and a combined master's and doctoral course researcher at UNIST’s Department of Materials Science and Engineering, explained, "The solid-liquid phase change of PEG is a reversible reaction, so simply repeating this process allows the magnetization pattern of the soft composite material to be easily redesigned (reprogrammed) as desired."

Material Capable of Self Paper Folding

Professor Kim Ji-yoon and Researcher Song Hyun-seo

Additionally, the research team implemented a magnetic soft actuator capable of 'self paper folding' using the developed composite material. They redesigned the actuator’s magnetization pattern in actual operating environments and exposed it to magnetic fields to realize various complex three-dimensional shapes. Because of the reversible reaction, the material maintains its performance even when new magnetization patterns are repeatedly input into the same actuator.

Professor Jiyoon Kim stated, "Unlike previous studies, this research is significant in that it developed a material capable of easily redesigning magnetization patterns without altering the intrinsic properties of magnetic particles or the polymer matrix." She added, "The developed material also has flexibility, and it is expected to play a key role in various fields requiring variable-structure smart materials, such as biomedical engineering, flexible electronic devices, and soft robotics."

This content was produced with the assistance of AI translation services.