Next time, when you see a cobweb in the forest, think about it: it is so strong that one such thread as thick as an adult would stand a jetliner! Scientists have long struggled with the solution of this riddle and finally revealed a secret: it turned out that the whole thing was in the unique structure of the spider’s web of hunters.
To find out why the web is five times stronger than steel, scientists studied the threads that the poisonous spider Loxosceles reclusa produces to create traps of networks and egg-laying containers. When a spider bites with an incredibly long paws, a person develops loxosselism – inflammation, and then gangrene scabs from dying tissue at the site of the bite. The researchers carefully examined the web with an atomic microscope and found one surprising circumstance. What the naked eye takes for one single thinnest thread (which is about 1000 times smaller than a human hair) is in fact a dense “rope” woven from hundreds of nanofibers. The diameter of one such fiber is 20 ppm. Like modern cables,
Not a very long fiber, is it? So it may seem at first glance. However, if we consider the structure at the micro level, it turns out that the length of such fiber can exceed the width by about 50 times – and the researchers are confident that they can stretch even more.
Nanofibres in the wild: the secret of strength
The idea that the web consists of nanofibers is not new and has already been discussed many times in the scientific community. However, until now, researchers could not provide evidence that nanoscopic filaments make up the entire web, and not its individual parts. The “secret weapon” of scientists in this case was the unique properties of the Loxosceles reclusa web. If the majority of spiders spin cylindrical threads, then the web of these is in fact flat, like a ribbon – this facilitated research under a powerful microscope.
The new discovery is based on an even earlier work that the team published a year ago. Then scientists found out that L. reclusa (also called “brown hermit spiders”) strengthens flat yarns using a special weaving technique. Like a living sewing machine, the spider interweaves about 20 micropieces into each millimeter of the web. Such “stitches” strengthen the sticky trapping net and give it incredible strength. The researchers claim that even if the shape of the threads and the weaving technique of other spiders are different, the new discovery may be the starting point for exploring the natural fibers that other species produce.
For humanity, this information is extremely important – knowing how nature creates ultrastrong and very light threads, we ourselves will be able to create their synthetic counterparts. An artificial web would be useful everywhere, from the military and medical industry to ordinary textiles. However, now it is extremely difficult to recreate such a fiber on an industrial scale, and nobody succeeded in it (although there were such attempts a couple of years ago). Scientists hope that further research will sooner or later put at the service of humanity one of the most complex and unusual materials in the world.