Friday, July 14, 2017

Non-toxic, stretchy artificial spider silk created by Cambridge University scientists could be used to make bulletproof vests


A new artificial spider silk that is super strong and stretchy has been developed by Cambridge University scientists.

The fibres that make up each strand work like miniature bungee cords and could one day be used to make bike helmets and even bulletproof vests.

The web-like fibres are non-toxic and are made by stretching a strand of 'silk' out from a soupy material called a hydrogel.

The silk is woven at room temperature using mostly water, meaning it is made using sustainable methods, the researchers said.


A new artificial spider silk (pictured) that is super strong and stretchy and made from 98 per cent water has been developed by scientists. The fibres, which work like miniature bungee cords, could one day be used to make bike helmets and even bulletproof vests

Dr Darshil Shah, co-author of the paper, told Digital Trends: '[Making current] synthetic fibres requires a tremendous amount of energy – up to 1,500°C (2,700°F) - and large use of solvents, that are difficult, toxic, and unpleasant to handle and dispose.

'On the other hand, we see that spiders have evolved over hundreds of millions of years to produce silk fibres with superb properties, on demand, from a gel with water as a solvent, at room temperature and pressure.' 

Chemical interactions between the silk's components allows for a long and thin thread to be gradually pulled from the hydrogel like a hot string of mozzarella.
The resulting threads are incredibly thin, with diameters of a few thousands of a millimetre.

The hydrogel the team use is 98 per cent water, with the other 2 per cent made up of solid substances in the form of modified silica and modified cellulose polymers.


In addition to its strength, the fibres also show very high damping capacity, meaning that they can absorb large amounts of energy. This is the characteristic that real spider webs need to have in order to absorb the impact of insects hitting their webs (stock image

What is most interesting is that this is the first ever, to our knowledge, supramolecular fibre,' Dr Shah said.

'What we mean by "supramolecular" is that there are no covalent bonds between the modified silica and cellulose polymers, but rather the interactions are all non-covalent.

'This dynamic cross-linking is important in giving the hydrogel the ability to stretch so much, and to form fibres in the first place.

'In addition, there is so much scope to modify the chemistry, by changing the cellulose polymer we have used, to make a whole family of fibres with interesting 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.

This is the characteristic that real spider webs need to have in order to absorb the impact of insects hitting their webs.

The material can dissipate close to 70 per cent of the energy in impacts, which beats even the damping capacity of some natural silks.

Dr Shah told Digital trends that there are a number of possible applications for the team’s artificial webbing.

These range from super strong and stretchy textiles to flexible biomedical applications.

In particular, the ability to absorb impacts could make it useful for future helmets for cyclists, American football players, skateboarders, and other extreme contact sports.

Previous research has shown that artificial spider silk could be used to make lighter bulletproof vests.

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


No comments:

Post a Comment