Spider silk is one of nature’s strongest materials, and scientists have been attempting to mimic its properties for a range of applications, with varying degrees of success

Spider silk is one of nature’s strongest materials, and scientists have been attempting to mimic its properties for a range of applications, with varying degrees of success

UK researchers have developed what they say is a "super stretchy, strong and sustainable material that mimics the qualities of spider silk, is 'spun' from a material that is 98% water" – and could be used to make textiles.

According to a team of architects and chemists from the University of Cambridge, 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.

The development is said to improve upon other methods of making synthetic spider silk, since it does not require high energy procedures or extensive use of harmful solvents. And it could substantially improve the process of developing all kinds of synthetic fibres without having to rely on high-energy, toxic methods, the scientists say.

Spider silk is one of nature's strongest materials, but so far attempts to mimic its properties for a range of applications have had varying degrees of success.

The fibres designed by the Cambridge team 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, which form long, extremely thin threads – a few millionths of a metre in diameter. After roughly 30 seconds, the water evaporates, leaving a fibre that is both strong and stretchy, says the team.

"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," explains  co-author Dr Darshil Shah from Cambridge's department of architecture. "However, 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-guest chemistry, which relies on forces other than covalent bonds, where atoms share electrons.

"When you look at these fibres, you can see a range of different forces holding them together at different scales," adds Yuchao Wu, a PhD student in Cambridge's department of chemistry, and the paper's lead author. "It's like a hierarchy that results in a complex combination of properties."

The strength of the fibres exceeds that of other synthetic fibres, such as cellulose-based viscose and artificial silks, as well as natural fibres such as human or animal hair.

In addition to its strength, the fibres also show very high damping capacity, meaning that they can absorb large amounts of energy, similar to a bungee cord. There are very few synthetic fibres which have this capacity, says the team, 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 silks.

"We think that this method of making fibres could be a sustainable alternative to current manufacturing methods," says Shah.

Looking ahead, the researchers plan to explore the chemistry of the fibres further, including making yarns and braided fibres.