An American brown recluse spider. Photo: Oxford University.Brown recluse spiders use a unique micro-looping technique to make their threads stronger than those of any other spider, a UK-US collaboration has discovered.
This research offers an explanation for how the spider is able to make its silk uncommonly strong. If applied to synthetic materials, the micro-looping technique could find a range of applications, including helping to improve the impact absorbing structures used in space travel.
The study, published in Material Horizons, was conducted by scientists from Oxford University's Department of Zoology, together with a team from the Applied Science Department at the College of William & Mary. Their surveillance of the brown recluse spider's spinning behavior shows how, and to what extent, the spider manages to strengthen the silk it makes.
From observing the arachnid, the team discovered that, rather than the round ribbons of thread produced by other spiders, the silk produced by brown recluse spiders is thin and flat. This structural difference is key to the thread's strength, providing the flexibility needed to prevent premature breakage and withstand the knots created during spinning to give each strand additional strength.
"The theory of knots adding strength is well proven, but adding loops to synthetic filaments always seems to lead to premature fiber failure," said Hannes Schniepp from William & Mary. "Observation of the recluse spider provided the breakthrough solution; unlike all spiders, its silk is not round but a thin, nano-scale flat ribbon. The ribbon shape adds the flexibility needed to prevent premature failure, so that all the microloops can provide additional strength to the strand."
By using computer simulations to apply this technique to synthetic fibers, the team were able to show that adding even a single loop would significantly enhance the fibers’ strength. "We were able to prove that adding even a single loop significantly enhances the toughness of a simple synthetic sticky tape," said William & Mary PhD student Sean Koebley. "Our observations open the door to new fiber technology inspired by the brown recluse."
Possible examples of this new technology were outlined by Fritz Vollrath from the Department of Zoology at Oxford University. "Computer simulations demonstrate that fibers with many loops would be much, much tougher than those without loops. This right away suggests possible applications," he said. "For example, carbon filaments could be looped to make them less brittle, and thus allow their use in novel impact absorbing structures. One example would be spider-like webs of carbon filaments floating in outer space, to capture the drifting space debris that endangers astronaut lives' and satellite integrity."
This story is adapted from material from Oxford University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.