MIT Labs Moves Ahead In Synthesizing Spider Silk 135
icepick72 writes in with a link to an ExtremeTech article on new methods for creating synthetic spider silk. This material, like lycra in many ways, has a number of unique properties. The MIT lab that created it is being monitored by military elements, keenly interested in applications of this material to front-line technologies. From the article: "The secret of spider silk's combined strength and flexibility, according to scientists, has to do with the arrangement of the nano-crystalline reinforcement of the silk as it is being produced--in other words, the way these tiny crystals are oriented towards (and adhere to) the stretchy protein. Emulating this process in a synthetic polymer, the MIT team focused on reinforcing solutions of commercial rubbery substance known as polyurethane elastomer with nano-sized clay platelets instead of simply heating and mixing the molten plastics with reinforcing agents."
Kevlar Replacement (Score:5, Informative)
The biggest interest was extremley light weight bullet proof clothing.
The military would be very interested if they can get their infantry to loose several kilo's of body armour.
SilkSteel Alloys (Score:3, Informative)
Not really spider silk but this is. (Score:5, Informative)
Spider silk is a kind made of protein and the feedstock is a liquid crystal
A company called Spinox Ltd (an Oxford University Spin off -- get it? ha ha ). Here is a note from a Smith Insitute workshop on the topic [smithinst.ac.uk].
This group is actually trying to emulate what goes on in a spider (biomimetics). The big advantage is that it uses harmless ingredients and low temperatures. Compare for example Kevlar, the manufacture of which needs concentrated sulfuric acid. Spinox details [isis-innovation.com]
Re:Back to spiders... (Score:5, Informative)
Long chain molecules contain lots of carbon-carbon bonds. The polythene thing you get at the top of a six-pack of beer has lots of these chain molecules, but it is fairly weak. Stretch a bit of it, and you will see a sudden jump between the fat, unstretched material, and the skinnier, stretched material. The stretched stuff is a lot less stretchy. What you have done when you stretched the thing was to align the molecules, so you have chains of carbon-carbon bonds in the direction you have stretched the thing. Mylar - the stuff you sometimes find inside bicycle wheels and protective cloting is strengthened in this way.
That is only part of the secret. A diamond is made of carbon-carbon bonds in every direction, but you can shatter a diamond, and when you do the energies absorbed by the diamond are pretty tiny. If you want to make something tough, you will need some strategy for the thing to yeild and absorb energy. Metals yeild when they are stressed beyond a certain point, but they can still keep their strength. Carbon fibre materials can crack, but the carbon fibres have two strategies for resisting the crack. The fibres can separate from the glue matrix. If a fibre lies across the gap, then a lot of work is necessary to pull the fibtre free of the matrix as the crack opens. If the fibre lies along the crack, it can stop the crack becayse the crack may run around the fibre surface, and so end up with a blunt tip (the sharper the crack tip is, the more it concentrates the stress). ness of the crack tip .
Another thing you will probably need in a sting is some ability to absorb energy without yeilding. Steel wire is a lot lighter for the same ability to support load, but climbers do not use it. The first thing a climber's rope needs to do is to absorb the energy from the falling climber. If it does not stretch, then the energy has to be absorbed over a small distance, so the force needed has to be that much bigger. Making where the threads so not go straight up and down have more 'give' in them.
Okay - I have cut a lot of corners in this explanation. There are scientific terms for strength, hardness, toughness, and things like that that are often confused in ordinary speech. However, I hope I have got across the basics - making long chain molecules isn't enough - you have to make them go up and down the thread; but not straight up and down or the thread will not stretch; and you have to glue them together with something sticky that absorbs energy as it yeilds. A spider's butt probably manages this because it is small, and the spinarets are a complex shape. All the bits seem do-able, but it's a good trick: people have been trying for many years, and we are not close yet. Maybe, there is another trick in there we haven't suspected yet.
PS: The process probably won't scale. So, you will have thousands of minature spider's butts, rather than one giant one.
Re:Back to spiders... (Score:3, Informative)
Re:DARPA's Real Power-Armor Research (Score:3, Informative)
Our suits give us better eyes, better ears, stronger backs (to carry heavier weapons and more ammo), better legs, more intelligence (in the military meaning...), more firepower, greater endurance, less vulnerability.
A suit isn't a space suit - although it can serve as one. it is not primarily armor - although the Knights of the Round Table were not armored as well as we are. It isn't a tank - but a single M.I. [Mobile Infantry] private could take on a squadron of those things and knock them off unassisted...
The real genius in the design is that you don't have to control the suit; you just wear it, like your clothes, like skin.
The secret lies in negative feedback and amplification.