A team of architects and chemists from the University of Cambridge have designed super-stretchy and strong fibres that are almost entirely composed of water, which could be used to make textiles, sensors and other materials.
The green method for making artificial spider silk, not only improves upon earlier methods of making synthetic spider silk, but it also doesn’t require high energy procedures or extensive use of harmful solvents. In addition, the scientist from Cambridge added that the method could also “substantially improve” methods of making synthetic fibres of all kinds, since other types of synthetic fibres also rely on high-energy, toxic methods.
The fibres, which resemble miniature bungee cords, are “spun” from a soupy material called a hydrogel that is 98 percent water. The remaining 2 percent 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 fibres 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 fibre which is both strong and stretchy. As well as these fibres possibly being used to make textiles they can also absorb large amounts of energy, are sustainable, non-toxic and can be made at room temperature.
“When you look at these fibres, you can see a range of different forces holding them together at different scales,” said 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.”
Co-author Dr. Darshil Shah from Cambridge’s Department of Architecture, added: “We have yet to fully recreate the elegance with which spiders spin silk, and 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.
“However, our fibres are non-toxic and far less energy-intensive to make.”
This research is the result of collaboration between the Melville Laboratory for Polymer Synthesis in the Department of Chemistry, led by Professor Oren Scherman; and the Centre for Natural Material Innovation in the Department of Architecture, led by Dr Michael Ramage, and was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) and the Leverhulme Trust.
Image: courtesy of William Waterway