Scientists from the University of Cambridge have developed super-stretchy and strong artificial silk, composed almost entirely of water, which may be used to make eco-friendly textiles and sensors.
The fibres, which resemble miniature bungee cords as they can absorb large amounts of energy, are sustainable, non-toxic and can be made at room temperature, researchers said. The fibres are spun from a soupy material called a hydrogel, which is 98% water. The remaining 2% of the hydrogel is 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 fibres to be pulled from the gel. The extremely thin threads are a few millionths of a metre in diameter. After the hydrogel is stretched for roughly 30 seconds, the water evaporates, leaving a strong fibre.
Although our fibres 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. Our fibres are non-toxic and far less energy-intensive to make. The fibres are capable of self-assembly at room temperature, and are held together by supramolecular host, where atoms share electrons. When you look at these fibres, you can see a range of different forces holding them together at different scales. It’s like a hierarchy that results in a complex combination of properties.