Unraveling the Web of Mystery Surrounding Spider Silk

Until recently, there was so little we knew about the physical properties of a spider web. Spider silk is one of the most unique fibers in the world, being able to endure all kinds of abuse like stretching and soaking, and still being able to function as normal afterwards. It is stronger than steel and stronger than Kevlar, the stuff that makes up bulletproof vests, when you compare it ounce for ounce.

Now, we know a lot more about spider silk, after a team of scientists was able to measure the elastic properties of an intact spider web and this increased knowledge should help with further innovations about silk that we previously mentioned in our blog here and here.

The Stanford researchers utilized a technique known as Billouin spectroscopy, which shines a laser at the spider web and then records the scattering of light to measure the mechanical properties of spider silk. In short, it is a much more complicated form of the spectrophotometry done in freshman and sophomore labs to measure absorbance values, except Billouin spectroscopy measure the mechanical properties of a material.

Measuring mechanical properties of spider silk using Billouin spectroscopy

The researchers learned that although spider webs are made of uniform spider silk, the stiffness and elasticity of the silk varies between individual strands. They also discovered that the silk stiffens in conditions of 100% humidity to produce a tighter web, a behavior known as supercontraction. The second discovery that adjusting water content to alter the mechanical properties of spider silk is especially interesting and Kristie Koski, the lead researcher, say could lead to new and exciting advancements.