Soft as skin, strong as steel: Powerful magnetic muscles lift 1000x their weight

Researchers have engineered a material that is as soft as skin but remarkably strong.

Ulsan National Institute of Science & Technology (UNIST) team in South Korea has developed an innovative magnetic composite artificial muscle. This new material can adapt its stiffness, transitioning from soft to rigid, and vice versa.

Interestingly, artificial muscle showcases “an impressive ability to withstand loads comparable to those of automobiles.”

Moreover, this material's stiffness is a mind-boggling 2,700 times that of traditional materials. This tech could significantly benefit soft robotics and wearable technology.

Strong artificial muscles

Soft, human-like artificial muscles are vital for robotics, wearables, and medical devices.

While traditional soft materials are great for smooth movements, they fall short regarding strength and precision. Particularly, the existing materials are too rigid 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 issues.

For this, they used materials that could switch between hard and soft states. The researchers combined two key 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 muscle's strength.

On the other hand, these polymers can change shape in response to specific stimuli (like heat or light) and then return to their original shape. This allows the muscle to be highly adaptable 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 bond the magnetic particles to the shape memory polymer.

This created a strong connection between the two materials, which improved the overall strength and performance of the artificial muscle.

In addition, this connection allows the muscle to respond quickly and efficiently to magnetic fields. When a magnetic field is applied, the magnetic particles react, causing the muscle to change shape. This rapid response enables precise and controlled movements.

"Utilizing multi-stimulation methods, including laser heating and magnetic field control, we can remotely execute fundamental movements such as elongation, contraction, bending, and torsion, along with more complex actions like manipulating objects with precision," Professor Jeong explained.

As per the press release, these muscles are incredibly adaptable, capable of changing their stiffness by 2,700 times and their softness by an impressive eightfold.

Notably, these materials can handle tensile forces 1,000 times their weight and compressive forces 3,690 times their weight.

These muscles are powerhouses of efficiency, converting a whopping 90.9% of the input energy into useful work.

The team also worked to lower the vibrations. The material incorporates an innovative double-layer design, featuring a vibration-damping hydrogel layer. This enables unprecedented control and reduces vibrations of the artificial muscle even at high speeds.

"This research opens avenues for transformative applications across diverse sectors, driven by mechanical properties and performance that transcend the limitations of existing artificial muscles,” Jeong concluded.

The study was published in the journal Nature Communications.