A cellar spider hangs in its silk web. Photo by Obsidian Soul/CC
TRENTO, Italy, May 5 (UPI) -- According to new research out of Italy, spiders sprayed with graphene and carbon nanotubes spin silk that is extra strong and stretchy -- an engineering wonder, part synthetic, part natural.
Graphene has been the darling of material science research for some time. Graphene is a material built of single atom-thick layers of graphite. The atoms in each layer are organized in a lattice-like structure. Graphene is flexible, strong, hyper-conductive, and has an endless list of commercial and technological applications.
In some ways, graphene replaced scientists' obsession with the silk threads spun by spiders, admired for many of the same qualities. Now, scientists have found a unique way to combine the advantages of the two materials.
Researchers discovered the phenomenon after spraying a handful of arachnids called cellar spiders with a graphene-water solution. The graphene particles suspended in the solution measured between 200 and 300 nanometers wide.
The team of researchers -- lead by Nicola Pugno of the University of Trento in Italy -- sprayed another group of spiders with a mixture of water and carbon nanotubes, another material admired for its unusual structural attributes.
While some of the sprayed spiders produced subpar silk, several from both groups spun extra-strong silk. The best silk fibers were spun by a cellar spider coated with the nanotube solution. The silk was 3.5 times strong than the strongest silk found in nature, produced by the giant riverine orb spider.
How the graphene and nanotubes ended up in the silk strands remains a mystery. It's possible that the solution leaked onto the silk as it exited the spider's spinneret.
But Pugno and his colleagues believe spiders have a biological mechanism for absorbing materials from their surroundings and incorporating them into their threads. For a few of the spiders, that strategy didn't pay off. Four died not long after being sprayed. But for others, the solution offered super powers.
But what might graphene-enhanced silk be used for? Pugno isn't sure.
"This concept could become a way to obtain materials with superior characteristics," he told New Scientist -- like a giant stretchable net strong enough to catch falling aircraft.
Pugno's research is scheduled to be published in the journal Materials Science.