New material for artificial muscles called stronger, more flexible than what's in body

Researchers have developed a new material for artificial muscles, using a film of dielectric elastomers as thin and light as human hair. Photo courtesy of Soft Materials Research Lab at UCLA
Researchers have developed a new material for artificial muscles, using a film of dielectric elastomers as thin and light as human hair. Photo courtesy of Soft Materials Research Lab at UCLA

July 7 (UPI) -- In the mode of the Bionic Woman and The Six Million Dollar Man, researchers have developed a new material -- and manufacturing process -- for artificial muscles that they describe as stronger and more flexible than their biological counterparts.

The research, published Thursday in Science, was led by materials scientists at the University of California, Los Angeles, together with colleagues at SRI International, an independent nonprofit scientific research institute based in Menlo Park, Calif.


Researchers described the new, durable material made to reproduce the function of muscles as a film created with layers of lightweight, processable, high-performance "dielectric elastomers."

Elastomers, or "electroactive polymers," are either natural or synthetic substances with large molecules that can change in size or shape when stimulated by an electric field.

The UCLA-led team's newly created film is "as thin and light as human hair," about 35 micrometers in thickness, the scientists said.


When multiple layers are stacked together, they become a miniature electric motor that can act like muscle tissue and produce enough energy to power motion for small robots or sensors.

The researchers have made stacks of films ranging from four to 50 layers.

Qibing Pei, a professor of materials science and engineering at UCLA's Henry Samueli School of Engineering and the study's corresponding author, told UPI in a phone interview that he envisions numerous potential medical applications for the new material, as well as its use in small robotics.

"The human body is a very complex machine with many muscles, and these artificial muscles could potentially go anywhere," Pei said.

For example, he said, the "artificial muscle" material might be used as wearable technology, perhaps placed on the skin to help people who cannot otherwise smile or blink due to health conditions.

Or, he said, there might be potential applications for the material to be implanted in the body, perhaps, for example, strengthening the sphincter muscle in a person with acid reflux.

Pei said the next step is to look for applications, which may require further modifications of the material.

"I think the potential is huge," but a lot of engineering is needed to realize that potential, Pei said. "So we hope others help develop practical applications."


Pei described creating an artificial muscle to enable work and detect force and touch as "one of the grand challenges of science and engineering."

That's because a soft material cannot be considered for use as an artificial muscle unless it is able to output mechanical energy and remain viable under high-strain conditions -- meaning it does not easily lose its form and strength after repeated work cycles, according to a news release.

Scientists have explored the issue for decades, and began work on dielectric elastomers in the late 1990s, Pei explained. But fundamental challenges remained that the UCLA team sought to resolve.

"We needed a material that can be readily formed and scaled up," he said. "You can print the artificial muscle to whatever shape and size that you need to do the work."

Dielectric elastomers, which are "lightweight materials with high elastic energy density," stand out because of their flexibility and toughness.

Yet, commercially available dielectric elastomers are made of acrylic or silicone and have limited capabilities, lacking flexibility or unable to withstand high strain, Pei said.

The UCLA-led team of researchers said they used an ultraviolet light curing process on commercially available chemicals to create an improved acrylic-based material "that is more pliable, tunable and simpler to scale without losing its strength and endurance."


The team has filed for an international patent on the new technology, Pei said.

Funding was provided by the Defense Advanced Research Projects Agency. DARPA describes its mission as making "pivotal investments in breakthrough technologies for national security."

Pei said DARPA is interested in new technologies, but the UCLA research is "open, not classified or controlled."

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