Ultra-Tough Polymer Exceeds Kevlar's Strength by Mimicking Spider Silk

Inspired by nature, researchers at Polytechnique Montréal have developed a polymer five to 10 times tougher than steel or Kevlar. The polymer is a fiber based on spider silk and has the ability to stretch considerably without breaking.

Professor Frédérick Gosselin, one of the main researchers, explained the mechanics of spider silk and how it results in such exceptional strength: “The silk protein coils upon itself like a spring. Each loop of the spring is attached to its neighbours with sacrificial bonds, chemical connections that break before the main molecular structural chain tears. To break the protein by stretching it, you need to uncoil the spring and break each of the sacrificial bonds one by one, which takes a lot of energy. This is the mechanism we're seeking to reproduce in laboratory.”

The researchers’ microstructured fiber is created by pouring a filament of viscous polymeric solution towards a moving sublayer. This causes the filament to form a series of coils, creating a regular, looping pattern. When the solvent in the material evaporates, leaving the fiber solidified, the result is a strong fiber that is 8-10 micros in diameter. The coils result in a springlike structure, mimicking spider silk.

The researchers foresee that their work could lead to the manufacture new safer and lighter casings for aircraft engines, which would prevent debris from dispersing in case of explosion. Many other applications can be foreseen, from surgical devices to bulletproof clothing to vehicle parts.

You can see a video of the machine creating the fiber here and  the press release here