Researchers are finally catching up with nature

Mar 15, 2010 09:42 GMT  ·  By
Materials scientists at MIT are making great progress in learning how to replicate the amazing mechanical properties of silk
   Materials scientists at MIT are making great progress in learning how to replicate the amazing mechanical properties of silk

For many years, materials scientists have been looking at spiders and silk worms with awe. These tiny animals know from instinct how to construct some of the toughest materials in the world. The silk they produce has enormously-interesting properties, including the fact that it's stronger and lighter than steel, if taken pound for pound. It is also less brittle than the metal, and scientists have been hoping to replicate it inside the tightly-controlled confines of labs for many years. However, these efforts have thus far been unsuccessful. Now, a new research effort manages to break some of the old barriers, ScienceDaily reports.

Thanks to the new datasets, experts are confident that they would soon be able to create synthetic materials that would either rival, or exceed, natural silk in terms of resistance. The investigation was conducted by specialists at the Massachusetts Institute of Technology (MIT) Department of Civil and Environmental Engineering. The team was led by scientist Markus Buehler, who is also the Esther and Harold E. Edgerton associate professor at the Department. He and his group conducted an exhaustive analysis on the strengths and weakness of natural silk, including the limits when it gives way.

In order to do this, the group had to develop a new computer model, that is capable of simulating the structure of the silk molecules, as well as the interactions that take place when more such molecules move past each other, and interact. What the team basically wanted to accomplish was gain the deepest view possible of these events, down to the molecular and atomic level. The thing about the atomic bonds that keep silk molecules together is that they are inherently very weak. However, their counter-intuitive strength comes from the unusual arrangement that these bonds have. Details of the new work appear in the March 14 issue of the respected scientific journal Nature Materials.

What puzzles materials scientists more about silk is the fact that it maintains its strength even if it's ductile. This is the property that allows for it to be bent and reshaped without losing its mechanical properties. “In most engineered materials, high strength comes with brittleness. Once ductility is introduced, materials become weak,” explains Buehler, adding that silk is not such a material. Its secret is the fact that beta-sheet crystals work together with filaments that join to produce reinforced chemical bonds.