A new synthesis method yields synthetic spider silk with threads of molecules held together by a unique variety of forces, making them extra stretchy and strong. Photo by University of Cambridge
July 10 (UPI) -- Scientists at the University of Cambridge have developed a new, more eco-friendly method for synthesizing spider silk. The extra stretchy, super strong fibers could be used in textiles, sensors and other technologies.
The synthetic spider silk fibers, which look like mini bungee cords, are made of mostly water. Unlike previous synthesis methods, the new technique doesn't require toxic solvents. The new method is also less energy intensive and can be performed at room temperature.
The new synthetic silk is spun from a hydrogel, composed of 98 percent water and 2 percent silica and cellulose. The combination of silica and cellulose feature molecular "handcuffs" called cucurbiturils, which hold the gel's molecules together and allow threads to be pulled from the gel solution.
Water evaporates from the pulled threads leaving behind a stretchy, strong fiber.
"Although our fibers are not as strong as the strongest spider silks, they can support stresses in the range of 100 to 150 megapascals, which is similar to other synthetic and natural silks," Darshil Shah, a material scientist in Cambridge's architecture department, said in a news release. "However, our fibers are non-toxic and far less energy-intensive to make."
The threads are held together by unique molecular structures, not covalent bonds.
Researchers detailed their breakthrough method this week in the journal PNAS.
"When you look at these fibers, you can see a range of different forces holding them together at different scales," said lead study author Yuchao Wu, a doctoral student in Cambridge's chemistry department. "It's like a hierarchy that results in a complex combination of properties."
Not only are the new fibers stronger than previous interactions of synthetic spider silk, they also can absorb more energy -- like a bungee chord.
"We think that this method of making fibers could be a sustainable alternative to current manufacturing methods," said Shah.