The next time you see a cobweb in the forest, think: it is so strong that one such thread as thick as an adult would withstand a jetliner! Scientists fought for a long time to solve this riddle and finally revealed the secret: it turned out that it was all about the unique structure of the spider's trapping network.
To find out why spider webs are five times stronger than steel, scientists studied the threads that the poisonous spider Loxosceles reclusa produces to create trapping nets and containers for eggs. When bitten by this spider with incredibly long legs, a person develops loxoscelism - inflammation, and then gangrene scabs from dying tissue at the site of the bite. The researchers carefully examined the spider web using an atomic microscope and discovered one surprising fact. What the naked eye takes for a single thinnest thread (which is about 1000 times thinner than a human hair) is actually a dense "rope" woven from hundreds of nanofibers. The diameter of one such fiber is 20 ppm of a millimeter. Like modern cables,each strand of the web consists of parallel nanostructures with a length of at least 1 micron.
Not a very long fiber, is it? It may seem so at first glance. However, if we look at the structure at the micro level, it turns out that the length of such a fiber can exceed its width by about 50 times - and the researchers are confident that they can stretch even more.
Nanofibers in nature: the secret to strength
The idea that the web is composed of nanofibers is not new and has been discussed many times in the scientific community. However, until now, researchers have been unable to provide evidence that nanoscopic filaments constitute the entire web, and not its individual parts. In this case, the unique properties of the Loxosceles reclusa web have become the "secret weapon" of scientists. If most spiders spin cylindrical threads, then the web of these is in fact flat, like a ribbon - this made it easier to study under a powerful microscope.
The new discovery builds on even earlier work that the team posted a year ago. Then scientists found out that L. reclusa (they are also called "brown hermit spiders") strengthen the flat threads using a special weaving technique. Like a living sewing machine, the spider weaves about 20 micro-loops into every millimeter of the web. These “stitches” strengthen the sticky trap net and give it incredible strength. The researchers say that even if the shape of the threads and the weaving techniques of other spiders are different, the new discovery could be a starting point for studying the natural fibers that other species produce.
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Conclusion
For humanity, this information is extremely important - knowing how nature creates super-strong and very light threads, we ourselves will be able to create their synthetic counterparts. Artificial spider webs would be useful everywhere, from the military and medical industries to ordinary textiles. However, now it is extremely difficult to recreate such a fiber on an industrial scale, and no one has succeeded in this (although there were such attempts a couple of years ago). Scientists hope that further research will help, sooner or later, put one of the most complex and unusual materials in the world at the service of humanity.
Vasily Makarov
