Spider Silk Inspires New, Ultra-Tough Fiber

Spider silk may be delicate looking, but it is known for its strength and durability. And it's these stunning properties that have inspired researchers at Polytechnique Montreal to channel their inner Spiderman and create a new, ultra-tough fiber.

Three to eight microns in diameter, spider silk may be light but it is five to 10 times tougher than steel or Kevlar. In large part, spider silk owes its exceptional strength - meaning its ability to absorb lots of energy before collapsing - to the molecular structure of the proteins it's made up of. Scientists have long tried to develop real-world products that mimic the characteristics of elongation and stretch-resistance that spider silk possesses, and now it seems they have finally done so.

"The silk protein coils upon itself like a spring. Each loop of the spring is attached to its neighbors with sacrificial bonds, chemical connections that break before the main molecular structural chain tears," researcher Frederick Gosselin, who helped lead the research, said in a statement. "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,"

They did so by making micrometric-sized microstructured fibers that have mechanical properties similar to those of spider silk.

"It consists in pouring a filament of viscous polymeric solution toward a sub-layer that moves at a certain speed. So we create an instability," explained Renaud Passieux, one of the researchers. "The filament forms a series of loops or coils, kind of like when you pour a thread of honey onto a piece of toast. Depending on the instability determined by the way the fluid runs, the fiber presents a particular geometry. It forms regular periodic patterns, which we call instability patterns."

It's this geometry that determines the mechanical properties and toughness of the fiber, like that of spider silk.

The researchers hope that one day this method will lead to better and stronger technologies, including surgical devices, bulletproof clothing and vehicle parts.

The findings were published in the journal Advanced Materials.

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