An artificial muscle capable of lifting 1,000 times its weight. This claim might seem like science fiction, but a new technology could revolutionize soft robotics and wearable devices. Behind this feat is an innovative composite material combining extreme flexibility and impressive strength.
These artificial muscles rely on a combination of shape-memory polymers and magnetic particles. The first element allows controlled deformation through the application of heat, while the magnetic particles enable precise control via external fields. This dual property allows the stiffness of the material to be modulated in unprecedented proportions, up to 2,700 times its softest state.
Soft robotics is inspired by living organisms to develop flexible and resilient machines adapted to complex environments. However, a major obstacle persisted: traditional materials, like silicone, lack robustness and load capacity. The advancements made in South Korea provide a solution to these limitations.
In a study published by
Nature, researchers from Ulsan National Institute of Science and Technology describe their design: an artificial muscle as flexible as skin and as strong as steel. This composite material can not only bend, stretch, or contract, but also lift loads up to 1,000 times its own weight.
The key to this achievement lies in the thermal and magnetic control of the system. At high temperatures, the muscle becomes malleable and adaptable. Once cooled, it regains its rigidity and original shape thanks to the memory properties of the polymer. This flexibility opens up possibilities in surgical robotics, dynamic prostheses, and wearable devices.
When exposed to a magnetic field, the material can stretch up to 800% of its initial length, while maintaining remarkable precision of movement. Its responsiveness allows it to perform complex tasks such as handling fragile objects or working in extreme conditions.
The research team also integrated a dual-layer architecture with a hydrogel that dampens vibrations. This innovation enhances the muscle's stability, even at high speed, and improves its energy efficiency, which reaches 90.9%.
These artificial muscles are not limited to their impressive strength. Their modularity could transform wearable and biomedical technologies, offering customized solutions to individual needs. Devices capable of accompanying human movements while boosting their strength could soon become a reality.
For Prof. Jeong, the project's lead, this discovery marks a crucial step toward overcoming the limitations of current materials, promising applications in sectors as diverse as industry, medicine, and advanced robotics.
a - Diagram showing the concept of monophasic composite muscle and its multiple functions.
b - (i) Chemical composition of the composite; (ii) SEM image of the microstructures; (iii) and (iv) TEM images of NdFeB microparticles.
c - (i) Mechanism of the poly(SMA-co-EGDMA); (ii-v) WAXS images of the composites in different states: crystallized, amorphous, stretched amorphous, and stretched crystallized. What is a shape-memory polymer?
A shape-memory polymer is a material capable of changing shape due to a stimulus, such as heat, and returning to its original configuration when the stimulus is removed. This property is based on a unique molecular structure.
These polymers are programmed to remember two states: a "deformed" state, activated by a stimulus, and an "initial" state, which they return to when the stimulus disappears. This behavior distinguishes them from conventional materials.
They are widely used in robotics, medicine, and industry. Their adaptability makes them ideal for creating intelligent devices, such as dynamic prostheses or artificial muscles. Their great flexibility and strength offer innovative solutions for technologies requiring a balance between rigidity and suppleness.
Article author: Cédric DEPOND