A diet of graphene flakes helps spiders spin super-webs
Spiders sprayed with water containing carbon nanotubes and graphene flakes have produced the toughest fibres ever measured, say materials scientists.
Spider silk, a fibre constructed from protein, is already stronger than almost anything man-made, matching alloy steel for tensile strength while being just a sixth as dense, MIT Technology Review reports. It is also ductile and can be stretched to five times its length.
Emiliano Lepore at the University of Trento in Italy have now worked out a way to incorporate carbon nanotubes into the silk, making it even stronger. The technique is simplicity itself. They simply sprayed 15 Pholcidae spiders a mixture of water containing the nanotubes or graphene flakes over the spider, which then wove the "carbon-fibre" silk.
While the researchers could confirm the silk contained the graphene or nanotubes, they don't really know how the mechanism works.
MIT Technology Review again:
One possibility is that the silk becomes coated with these carbon-based materials after it is spun. Lepore and co cannot rule this out but say it is unlikely because the resulting structure would not have the strength they measured. “Such external coating on the fibre surface is not expected to significantly contribute to the observed mechanical strengthening,” they say.
Instead, the team say it is more likely that the spiders ingest the water along with the carbon-based materials and these are then incorporated into the fiber as it is spun. So the nanotubes and graphene end up in the central part of each fiber,e where they can have the biggest impact on its strength.
The next challenge, if there is to be an industrial application of the find, is to discover a way to harvest spider silk.
But for now, we can just add another to the list of extraordinary uses and properties of graphene.