as a wonder membrane?
I was having a bit of a wikipedia binge on graphene and its properties and noticed that it has been shown to have potential as a membrane that is neither gas or liquid permeable but yet can pass water vapour was well as if there was nothing there...?!?
Anyone comfortable reading the scientific literature could start here: http://www.condmat.physics.manchester.ac.uk/pdf/mesoscopic/publications/graphene/2012%20science%20water.pdf
Didn't get too far before it was quite obviously well beyond me...
I'd certainly not claim to understand it all - but the statement that intrigued me was when the team found that water was evaporating as fast from the container (measured as weight loss of the contents) with the Graphene Oxide membrane as when the container was open :
Unexpectedly, we observed a
huge weight loss if the container was filled with
water. Moreover, the evaporation rate was practically
the same as in the absence of the GO film;
that is, for the open aperture (Fig. 2A and fig. S3)."
I suspect that this will find applications in military/industrial applications where you could protect a person from hazardous gases & liquids while still allowing perspiration to escape. Later... maybe... it'll have a helmet-compatible hood and contrasting colour zips
Some good stuff here too.
First applications in weaponery? - really John, you're too old to be so cynical!
thanks for the links grumps. a truly strange substance.
i tried to read it john. the Samaritans phones were engaged.
Thanks for that. They allude to water purification as a potential application, and the fact that it only detectably impedes water when the layer is "several micrometers" thick is interesting, as that is getting to be a handlable thickness.
Allowing water to pass unimpeded in either direction whilst blocking even helium is impressive. Pobably no good for breathable waterproofs, though...
i think its only one atom thick.
thats too thin for these uses.
its very conductive and has applications in electronics.
also - silicene
A single sheet is one atom thick. But there's nothing stopping you having more than one.
It is actually talking about graphene oxide
So would be multiple layers of that
What an excellent paper - cheers for pointing it out; these Manchester boys are pretty good at the moment... What struck me was how the GO seems to act exactly like a normal membrane (eg. PTFE or PU etc) with respects to pressure differences on either sides of it, but behaves in a completely bizarre way with the water selectivity.
I don't think graphene or its derivatives will be used in the outdoor industry's waterproof clothing in the near future. However, this is a membrane that has unbelievable selectivity, and someone now need to work out the reason for this efficacy (the paper doesn't give a full explanation) then see if it can be modelled in more conventional polymers. If the spaced monolayers can be made in PTFE, or, preferably, PE, then they would likely have the same properties as the GO, which would be powerful indeed. Not only that, but the selectivity could be tuned to provide barriers for different solvents or chemicals, which would be vital to haz-suits and chem-weapon guys. There's probably another Nobel Prize in that.
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