University of Cambridge scientists designed super-stretchy, and strong fibers which entirely composed of water. The fibers used to make textiles, sensors and other materials.
The new method not only improves upon earlier methods of making synthetic spider silk. Since, it does not require high energy procedures or extensive use of harmful solvents, but it improve methods of making synthetic fibers of all kinds. Spider silk is one of nature’s strongest materials. Scientists attempting to mimic its properties for a range of applications, with varying degrees of success. “We have yet to fully recreate the elegance with which spider’s spin silk,” said, co-author Dr. Darshil Shah.
The fibers are “spun” from a soupy material called a hydrogel, which is 98% water. The remaining 2% of the hydrogel made of silica and cellulose. Both, naturally available materials held together in a network by barrel-shaped molecular “handcuffs” known as cucurbiturils. The chemical interactions between the different components enable long fibers pulled from the gel.
The fibers are pulled from the hydrogel, forming long, extremely thin threads, a few millionths of a metre in diameter. After roughly 30 seconds, the water evaporates, leaving a fiber which is both strong and stretchy. The new 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. However, the new fibers are non-toxic and far less energy-intensive to make.
The fibers capable of self-assembly at room temperature, and held together by supramolecular host-guest chemistry, which relies on forces other than covalent bonds, where atoms share electrons. The strength of the fibers exceeds that of other synthetic fibers, such as cellulose-based viscose and artificial silks. Also, natural fibers such as human or animal hair.
The fibers also show very high damping capacity, meaning that they can absorb large amounts of energy. Very few synthetic fibers have this capacity, but high damping is one of the special characteristics of spider silk. The researchers found that the damping capacity in some cases even exceeded that of natural silk. They plan to explore the chemistry of the fibers further, including making yarns and braided fibers.
More information: [PNAS]