Spider silk is one of nature’s engineering triumphs, stronger on a per-weight basis than steel. Scientists reported last week that they had made it many times stronger by infiltrating it with atoms of metals such as titanium, aluminum and zinc. The process might eventually lead to new types of strong and light material similar to carbon fiber.
The discovery, made by Seung-Mo Lee, a graduate student in engineering at the Max Planck Institute in Germany, occurred largely by chance. One of the techniques he uses is “atomic layer deposition” (ALD), in which substances are thinly coated with another material, often a metal. The lab where he works is cluttered and, as it turns out, home to many spiders. So one day two years ago, Lee got the idea of testing the ALD process on spider silk.
Lee found an Araneus arachnid with a drag line, reeled the thread in over a paper clip and put it in the ALD chamber.
When he took it out, it was almost a different material. He could hold the thread with a pair of tweezers — dragline thread is somewhat less sticky than web thread — and bounce the paper clip up and down without breaking the strand.
“We expected to see it breaking down, and indeed it happened the opposite,” said his supervisor, Mato Knez.
ALD infiltrated soft materials with metal atoms in addition to depositing atoms in a thin surface film.
