For centuries we have envied spiders for their ability to create elegant webs. Although fragile in appearance, spider silk may be six times stronger than steel by weight, but it is its toughness that makes it so special.
The threads which make up these remarkable structures are biopolymers. But before we can produce and use artificial spider silk, we need to understand what gives it its unique mechanical properties.

Experiments carried out at the ILL and ESRF, in collaboration with the Department of Zoology of the University of Oxford, have provided researchers with a new insight into how the silk's structure is organised, which can then be related to its mechanical properties. The results showed that spider silk is a hierarchically organized material. Its composite biopolymer structure includes different proteins which form so-called nanofibrils, which consist of alternating nanometre-sized crystalline structures and semi-amorphous regions. The nanofibrils are themselves embedded in an amorphous matrix. The crystals reinforce the fibre while the amorphous region gives extensibility and transfers load between the nanofibrils.

Many different research fields are interested in spider silk. Researchers envisage using a copy of this polymer as a medical suture or in ligament repair, because it does not tire when frequently flexed and can withstand regular impact and great pressure. The military sector is also interested in this material because its ability to dissipate energy could make it ideal for lightweight armour.