Skip to Content
Biotechnology

Nanotube Muscles Bench 50,000 Times Their Own Weight

Carbon nanotube yarns powered by light or electricity can run motors, flip a catapult, and lift impressive amounts of weight.
November 15, 2012

Yarns woven from carbon nanotubes can contract like muscles at extremely high speeds to lift large weights. These carbon nanotube muscles can lift loads 200 times greater than natural muscles the same size. Videos made by researchers at the University of Texas at Dallas show the nanotube yarns lifting loads as much as 50,000 times greater than their own weight.

Artificial muscles might be used as actuators in robotics and surgical tools, and drive tiny motors and flywheels. The nanotube muscles can be powered by electricity, but they also contract in response to light and certain chemicals. And they work at temperatures as high as 2,500 degrees Celsius, an extreme that reduces other strong actuating materials to a molten puddle. And unlike previous carbon nanotube muscles, these materials require no packaging or battery-like electrolytes to function. The yarns are described today in the journal Science.

Individual carbon nanotubes are stronger than steel, highly conductive, have great optical properties, and so on—you’ve heard the hype. But single nanotubes are not so useful. For many years, when researchers tried to build things out of them, they had trouble getting these properties to scale from single tubes to larger structures. One problem is the tendency for nanotubes to form spaghetti-like tangles, where each point of tube-to-tube contact can compromise strength. But over the past few years materials scientists have been learning how to straighten out these tangles and build large, useful things.

The trick in this case is a set of yarn-weaving techniques developed by Ray Baughman at the University of Texas at Dallas. His group starts by growing a vertical forest of carbon nanotubes, then dragging a roller over the top. As the tubes are pulled, they come together in a thin, stretchy sheet. The nanotubes in the sheet are all lined up like spaghetti in a box, and this alignment helps maintain their individual strength on a collective level. To make the nanotube muscles, the Texas researchers coat this sheet with a filler material that expands dramatically when heated. Then they weave the sheet into yarns with different twisting configurations. When the yarns are heated, the filler expands dramatically, and the yarn will contract in a way that’s determined by its coiling configuration.

Deep Dive

Biotechnology

How scientists want to make you young again

Research labs are pursuing technology to “reprogram” aging bodies back to youth.

Human brain cells transplanted into baby rats’ brains grow and form connections

When lab-grown clumps of human neurons are transplanted into newborn rats, they grow with the animals. The research raises some tricky ethical questions.

Inside the billion-dollar meeting for the mega-rich who want to live forever

Hope, hype, and self-experimentation collided at an exclusive conference for ultra-rich investors who want to extend their lives past 100. I went along for the ride.

The debate over whether aging is a disease rages on

In its latest catalogue of health conditions, the World Health Organization almost equated old age with disease. Then it backed off.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.