Scientists at MIT have taken inspiration from cucumber tendrils, the helical offshoots that grab onto fences and anything else they can, to create artificial muscle-like fibers. The new fibers can quickly contract and expand, and can lift objects many times their weight. The hope is that these may one day find their way into medical devices to help power ailing hearts, to give arm and leg prostheses more strength and agility, and to restore injured muscle tissue.
Using a fiber-drawing technique, these mini muscles are created with different polymers, each with its own thermal expansion characteristics. As the fiber is slightly heated, one material can bend better than the other, and if they’re intertwined just right inside the fiber, the whole fiber bends and turns into a helix.
As the fiber goes from straight to highly wound, it creates a strong pull on the tip. What’s interesting is that slight changes in temperature produce differences in the strength of the pull, allowing for careful control of the force that the fiber generates. By tweaking how the fiber is stretched during manufacturing, one can also control how responsive it will be to different temperature changes. The researchers had their fibers go through tens of thousands of contractions and they remained viable and in great working condition after all that.
Here are a few videos of examples of the new “muscles” being put to work:
Study in Science: Strain-programmable fiber-based artificial muscle