As a cucumber plant grows, it sprouts tightly coiled tendrils that seek out supports in order to pull the plant upward.
The new fibers were developed by MIT postdoc Mehmet Kanik and MIT graduate student Sirma Örgüç, working with professors Polina Anikeeva, Yoel Fink, Anantha Chandrakasan, and C. Cem Ta?an, and five others, using a fiber-drawing technique to combine two dissimilar polymers into a single strand of fiber.
As soon as Kanik picked up the coiled fiber for the first time, the warmth of his hand alone caused the fiber to curl up more tightly.
Following up on that observation, he found that even a small increase in temperature could make the coil tighten up, producing a surprisingly strong pulling force.
Then, as soon as the temperature went back down, the fiber returned to its original length.
In later testing, the team showed that this process of contracting and expanding could be repeated 10,000 times "and it was still going strong," Anikeeva says.