Researchers have developed a material that is as soft as skin, but remarkably strong.
The team from the Ulsan National Institute of Science & Technology (UNIST) in South Korea has developed an innovative magnetic composite artificial muscle. This new material can adjust its stiffness, from soft to stiff, and vice versa.
Interestingly, artificial muscles “display an impressive ability to withstand loads comparable to those of automobiles.”
Moreover, the stiffness of this material is no less than 2,700 times greater than that of traditional materials. This technology could significantly benefit soft robotics and wearable technology.
Strong artificial muscles
Soft, human-like artificial muscles are essential for robotics, wearables and medical devices.
While traditional soft materials are great for smooth movement, they fall short in strength and precision. In particular, existing materials are too stiff to lift heavy weights and too flexible to maintain precise control.
In this new development, researchers led by Professor Hoon Eui Jeong from the Department of Mechanical Engineering have tried to overcome these problems.
For this they used materials that could switch between hard and soft states. The researchers combined two important materials: ferromagnetic particles and shape memory polymers.
The ferromagnetic particles respond to magnetic fields, allowing the muscle to be controlled remotely. They also contribute to the strength of the muscles.
On the other hand, these polymers can change shape in response to specific stimuli (such as heat or light) and then return to their original shape. This allows the muscle to adapt very well and change its stiffness.
By combining these two materials, the researchers created a new type of artificial muscle that is both strong and flexible.
Incredible stiffness
The researchers used a special ‘surface treatment’ to bind the magnetic particles to the shape memory polymer.
This created a strong bond between the two materials, improving the overall strength and performance of the artificial muscle.
In addition, this connection ensures that the muscle can respond quickly and efficiently to magnetic fields. When a magnetic field is applied, the magnetic particles react, causing the muscle to change shape. This fast response allows precise and controlled movements.
“Using multi-stimulation methods, including laser heating and magnetic field control, we can remotely perform fundamental movements such as extension, contraction, bending and torsion, along with more complex actions such as precisely manipulating objects,” explains Professor Jeong .
According to the press release, these muscles are incredibly adaptable: they can change their stiffness 2,700 times and their softness as much as eightfold.
In particular, these materials can withstand tensile forces of 1000 times their weight and compressive forces of 3690 times their weight.
These muscles are powerhouses of efficiency, converting as much as 90.9% of input energy into useful work.
The team also worked to reduce vibrations. The material has an innovative double-layer design with a vibration-dampening hydrogel layer. This enables unprecedented control and reduces vibration of the artificial muscle, even at high speeds.
“This research opens up possibilities for transformative applications across industries, driven by mechanical properties and performance that transcend the limitations of existing artificial muscles,” Jeong concluded.
The research was published in the journal Nature communication.
