Silk spiders are pretty impressive on their own. They can create fibers that rival high-grade alloy steel for tensile strength. However, when spritzed with water containing carbon nanotubes and graphene flakes, these tiny spiders created the toughest fiber ever measured in a lab. The new spider silk was even stronger than Kevlar and knotted fibers. Could these super silk spiders soon be spinning out the most effective bullet-proof armor humanity ever seen?
MIT Technology Review reports that Emiliano Lepore from the University of Trento in Italy made an amazing discovery when he sprayed some silk spiders with a combination of carbon nanotubes and graphene flakes. It has long been noted that the protein fibers created by silk spiders is incredibly tough. Silk spiders are able to create a fiber that is as tough as high-grade alloy steel, but is about a sixth as dense. Despite its extreme strength and durability, it is also highly ductile and can be stretched as much as five times its length. Therefore, Lepore had the idea to attempt to improve upon what Mother Nature was already doing so effectively by adding a little man-made science into the mix.
Lepore first collected 15 wild Pholcidae spiders and tested the silk fibers they produced. These tests were used as the baseline for the untainted spider silk. Next, the team introduced graphene flakes and carbon nanotubes to the filbers by simply spraying the spiders with a water mixture containing the properties. As a result, the spiders began to spin silk fibers that contained nanotubes and graphene just by being sprayed with the mixture.
The resulting fiber was stronger than anything that had ever been measured before. The graphene/nanotube spider silk was stronger than Kevlar and knotted fibers yet maintained its ductile nature.
“We measure a fracture strength up to 5.4 GPa, a Young’s modulus up to 47.8 GPa and a toughness modulus up to 2.1 GPa. This is the highest toughness modulus for a fibre, surpassing synthetic polymeric high performance fibres (e.g. Kelvar49) and even the current toughest knotted fibers.”
Ultimately, these spiders were able to produce fibers stronger than anything created by humans simply by being sprayed with a nanotube- and graphene-infused water. The scientists note that though the findings are rather amazing, there are still many challenges ahead for the team, as there is no effective means to harvest spider silk. Therefore, the team says it would be important to develop a technique to harvest the spider silk on an industrial scale without harming the spiders.
[Image Credit: Getty Images/ Dan Kitwood]