Scientists Unravel Mysteries to Spider Silk Strength Using Lasers

They may be creepy and crawly, but spiders produce some of the world's strongest material: silk. Weight for weight, spider silk is five times as strong as piano wire. Now, scientists at Arizona Statue University have announced that they have found a way to obtain a wide variety of elastic properties of the silk of several intact spiders' webs using a sophisticated laser light scattering technique.

Scientists used an extremely lower power laser (less than 3.5 milliwats) and aimed it through spider webs. With this technique, they were able to spatially map the elastic stiffness of each web without disturbing it. They found variations among discreet fibers, junctions, and glue spots.

Overall, they studied four different types of spider's webs. They included Nephila clavipes, A. aurantia (gilded silver face), L. Hesperus (western black widow) and P. viridans (green lynx spider). All of these spiders' webs possessed major silk elastic properties.

But the researchers didn't only study the structure of silk, they also studied supercontraction, a property unique to silk. Spider silk soaks up water when exposed to high humidity, and this absorbed water can lead to shrinkage in an unrestrained fiber-up to 50 percent shrinkage in N. clavipes silk. Yet the spider silk is versatile, and this supercontraction helps the spider tailor the actual properties of the silk it produces during spinning.

Their information could help provide a blueprint for the structural engineering of a large array of materials. It could create everything from clothing to rope, and could allow materials to be stronger, stretchier, and more elastic.

The study was published in the online issue of Nature materials.