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A Liquid That Turns Solid When Heated
Roland Piquepaille writes "There are some sure things in life, such as death and taxes. When you are heating a solid, you expect it will melt and when you're boiling water, you're pretty certain that it will turn into vapor. But what about a liquid that becomes solid when it's heated? Of course, it has already been done, for example in the chemical process of polymerization. But now, PhysicsWeb writes that a team of French physicists has discovered a law-breaking liquid that defies the rules. When you heat it between 45 and 75C, it becomes solid. But the process is fully reversible, and this is a world's premiere. When you decrease the temperature, this solid melts and turns again into a liquid. I'm not sure of the implications of such a phenomenon, but it's fascinating. Read more for essential details."
Plazanet and colleagues prepared a liquid solution containing a-cyclodextrine (alpha-CD), water and 4-methylpyridine (4MP). Cyclodextrines are cyclic structures containing hydroxyl end groups that can form hydrogen bonds with either the 4MP or water molecules.
What I see:
And if you expect me to tell you how this discovery will modify our lives, you're going to be disappointed. I've not a slightest idea about it, even if I find fascinating that scientists always find new ways to break rules and shake our certitudes.
I don't know much about physics, but could something like this be used as a heat shield of some kind? Like, where the shield is basically considered turned off when it is in the liquid state. Then when it hits a certain overload temperature, it turns to a solid and thus blocks (some of) the heat exchange?
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Why do I see a new line of sex toys being based on this?
;)
Or at least a splint that packs down small but that remains rigid when in contact with a warm body.
Um.. Maybe that would apply to a sex toy
Wherever You Go, There You Are
Not that I can read the article yet (due to slowness), but the summary doesn't say what happens after 75C. It might melt again and that would be bad. If true, this chemical will possibly force the scientific community to reevaluate chemical laws and make new, more general (and therefore better) ones.
Slashdot is proof that Sturgeon's Law applies to mankind.
It doesn't break any law, it follows every law. Physics around phase-changes (liquid-solid, gas-liquid, gas-solid) can be really weird. Iodine sublimes (goes from solid crystal form to gas with no intermediate liquid form) for example, at least at STP.
:-)
:-))
It's almost certainly those pesky hydrogen bonds - they're responsible for just about everything interesting in organic chemistry... Strange how things ultimately come down to geometry
It is new and strange, but I'd be willing to bet just about anything that the physical laws of energy conservation, attraction and conversion are being rigorously adhered to
Simon
Physicists get Hadrons!
After reading the article (the actual publication, that is), here's an attempt at a summary.
When you heat something, the entropy (disorder) of a system increases in importance. This is a law of thermodynamics.
A gas has greater entropy than a liquid, both have greater entropy than a solid. Usually.
Now, this substance turns solid when you heat it. -This means the solid phase has higher entropy than the liquid phase. That is unusual, but it doesn't violate any laws.
How does it work? Well, it appear the alpha-cyclodextrin molecule has two conformations (shapes). In the low-temperature one, it hydrogen-bonds to itself. At higher temperatures, these bonds are broken. (this is what happens with ice-water-steam too)
The funny thing about this substance, is that once these internal hydrogen bonds are broken, it allows the molecule to bind to other ones.. so while you break the "internal" hydrogen bonds, you give rise to a bunch of "external" molecular bonds, to other alpha-cyclodextrine molecules.
This leads to the formation of a solid. (not actually a true solid, but rather a 'sol', a suspension of linked-together alpha-Cyclodextrin molecules in water) And this solid actually does have lower entropy than the liquid phase, due to the breaking of the internal hydrogen-bonds.
No laws broken. Nothing 'impossible' going on. But, it is however an interesting phenomenon, and something which certainly may turn out to have practical uses in the future.
Shock absorbers. This stuff would make fantastic shock absorbers.
Reinforcement for solid structures. Somebody already mentioned skyscrapers, but I'm also envisoning other more improbable structures, like hurricaine proof buildings. Wind blows, soften up the beams and let her bend a bit. Wind stops, stiffen the supports back up.
Mecha. This has to be used in mecha. Beams that can bend a bit, be solid or fluid, would be excellent in 50 foot killer robots. You know it.
Tank armour. Make it solid and when stuff hits, it breaks. Change temperature, and it melts. Change temp again and it becomes solid again, with no signs of previous damage. Regenerating armour.
Weaselmancer
rediculous.
hot enough to melt the beams
Even with jet fuel it wasn't enough to melt the steel. The problem is that steel loses much of it's strength at high temperatures, making it liable to bend or snap under load.
Also, and I relize your are replying to someone else's idea here, but I fail to see any logic in using this stuff in construction. What possible benefit is there in having the material be liquid at low temperatures? Instead of adding this stuff "in case of fire" you're better off using some ordinary building material that will be stronger at both low and high temperatures.
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