Scientists create super stretchy, strong and sustainable artificial spider silk that works like a “miniature bungee cord”

A team of architects and chemists from the University of Cambridge have created a super stretchy, strong and sustainable artificial spider silk.

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

Described as a  “miniature bungee cord” because of its ability to absorb large amounts of energy, the new artificial spider silk is ‘spun’ from a material that is 98% water and could be used to make textiles and sensors.

The technique used to create the new silk improves upon earlier methods of making synthetic spider silk because it doesn’t require high-energy procedures or extensive use of harmful solvents, and it could substantially improve methods of making synthetic fibres of all kinds, since other types of synthetic fibres do rely on high-energy, toxic methods.

“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,” said Dr Darshil Shah from Cambridge’s Department of Architecture.

“However, our fibres are non-toxic and far less energy-intensive to make.”

The fibres designed by the Cambridge team are “spun” from a material constructed from naturally available materials called hydrogel, which is 98% water and 2% silica and cellulose.

By combining the different components, the scientists are able to pull long spider silk-like fibres from the gel.

After roughly 30 seconds, the water evaporates, leaving extremely thin threads behind – a few millionths of a metre in diameter – which are both strong and stretchy.

Image courtesy of William Waterway

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, 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,” said Shah. The researchers plan to explore the chemistry of the fibres further, including making yarns and braided fibres.

Scientists expect California will get wetter with increased rainfall to come over the course of this century

New research, published today in the journal Nature Communications, is predicting that California will experience more rainfall through to the end of this century.

In contrast to previous climate models that predicted California would get warmer and drier during the rest of the century, scientists from the University of California, Riverside predict the state will get an average of 12% more precipitation in the remaining years of this century, compared to the last 20 years of last century.

Most previous research has emphasised uncertainty with regards to future precipitation levels in California, but the overall thought was California would become drier with continued climate change,” said Robert Allen, an associate professor at UC Riverside and one of the authors of the paper.

“We found the opposite, which is quite surprising.”

Image courtesy of UC Riverside Strategic Communications

The scientists analysed 38 climate models developed around the world to reach their conclusions.

They found that warming in the tropical eastern Pacific Ocean sea surface temperatures, an area about 2,500 miles east of the international date line, is the main reason for the predicted increase in precipitation levels.

The warming sea surface temperatures encourage a southeastward shift of the jet stream, which helps steer more rain-producing, mid-latitude cyclones toward California.

“Essentially, this mechanism is similar to what we in California expect during an El Nino year,” Allen said.

“Ultimately, what I am arguing is El Nino-like years are going to become more the norm in California.”

Ojai, California

Despite the scientists’ prediction being applied to the whole of California, they actually found a marked difference between the rate of rainfall for northern, central and southern California.

Northern California, which they define as starting just north of Santa Rosa, would increase 14.1%. Central California, which starts just south of San Luis Opispo, would go up 15.2%. Southern California would actually decrease 3.3%.

They also found the winter months of December, January and February, when California traditionally gets the bulk of its precipitation, would account for much of the overall increase in precipitation.

During those three months, precipitation levels would increase 31.6% in northern California, 39.2% in central California and 10.6% in southern California.

All these percentages are in comparison to data from the Global Precipitation Climatology Project observed between 1979 and 1999.