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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."
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 75, 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...
Here is the summary from PhysicsWeb.
Physicists in France have discovered a liquid that "freezes" when it is heated. Marie Plazanet and colleagues at the Université Joseph Fourier and the Institut Laue-Langevin, both in Grenoble, found that a simple solution composed of two organic compounds becomes a solid when it is heated to temperatures between 45 and 75, and becomes a liquid when cooled again. The team says that hydrogen bonds are responsible for this novel behaviour.
Ready for the scientific 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.
At room temperature, up to 300 grams of alpha-CD can be dissolved in a litre of 4MP. The resulting solution is homogenous and transparent, but it becomes a milky-white solid when heated. The temperature at which it becomes a solid falls as the concentration of alpha-CD increases.
Neutron-scattering studies revealed that the solid phase is a "sol-gel" system in which the formation of hydrogen bonds between the alpha-CD and the 4MP leads to an ordered, rigid structure. At lower temperatures, however, the hydrogen bonds tend to break and reform within the alpha-CD, which results in the solution becoming a liquid again.
The research work has been published by The Journal of Chemical Physics in its September 15, 2004 issue under the name "Freezing on heating of liquid solutions." Here is a link to the abstract.
We report a reversible liquid-solid transition upon heating of a simple solution composed of a-cyclodextrine (alpha-CD), water, and 4-methylpyridine. These solutions are homogeneous and transparent at ambient temperature and solidify when heated to temperatures between 45 and 75. Quasielastic and elastic neutron scattering show that molecular motions are slowed down in the solid and that crystalline order is established. The solution "freezes on heating." This process is fully reversible, on cooling the solid melts. A rearrangement of hydrogen bonds is postulated to be responsible for the observed phenomenon.
If you are interested by the subject, visit a university library, or buy the article for $22.
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.
[Additional note for physicists: I've been forced to use the "alpha-CD" notation here, because neither my publishing software nor my browsers seem to be able to understand the correct notation, which is "CD."]
Sources: Belle Dumé, PhysicsWeb, September 24, 2004; The Journal of Chemical Physics, September 15, 2004, Volume 121, Issue 11, pp. 5031-5034 Netcraft confirms *BSD is dying. 6:25:24 PM Permalink Comments [0] Trackback [0] Technorati about this page and this post
> In other news:
Cookie dough batter turns to solid in oven when heated. (Yeah, yeah, it's not reversible...)
I was thinking about that as well. But I think that cookie dough just turns solid because the water in it slowly evaporates and not because the molecules stop moving (or move slower).
You're confusing expansion with turning solid. Water is one of the few (only?) substances that expands when it freezes.
No. That law in the strictest sense only applies to pure substances.
We've already got good thermometers. How would this magically be better?
Actually, it becomes solid when it begins to cool. Not before. Though, if you left it in the oven long enough it'll go to solid black pretty quick!
Which law would this be? The one that says solids melt into liquids at higher temperatures? Oh wait, there is no such law - thanks to something called Sublimiation where solids go straight to a gas (like dry ice).
This is not an example of a new found element with impossible thermal properties. This is an example of materials and molecular chemistry in action. This works because it follows the laws of physics.
Good call. Here is a short explanation for those who are scratching their heads over what 'that program from The Recruit' might possibly have to do with solid liquids. Short answer: It doesn't; start reading more books!
I hear there's rumors on the Slashdots
That would probably depend on the property of the solid that forms when the solution is heated (is it a good insulator? what are its structural properties?), but I can think of one related application: temperature-controlled switch.
The solution is transparent to visible light, whereas the solid that forms is not. Since this process depends on the temperature and is reversible, it's very simple to design a circuit (using a LED and phototransistor or some sort of photo-detector) that works as temperature-dependent switch. From what the article says,
The temperature at which it becomes a solid falls as the concentration of CD increases.
it should be possible to tweak the turn-on temperature to a degree.
But then, this is not anything new--as far as dependence on temperature goes, there are many other materials that are probably more reliable (the only thing novel about this would be that its dependence is backward.)
Back to the topic, yeah, it can probably be used as heat shield in a limited capacity: i.e. if it turns out that the liquid is transparent to infrared radiation while the solid isn't, this can be used as natural temperature-controlled infrared radiation shield (but of course, it will still be subject to heating due to other methods, like...conduction via the solid itself, unless the resulting solid turns out to be similar to styroform).
I wouldn't be too sure about that.
Bose-Einstein Condensate
Superfluids
First rule of physics: When you're dealing with extremes, things get funky.
The rules of freezing, melting and vaporising (yes, I missed out sublimation) are not broken here. Chemists have known for some time that certain reactions can both only take place at a certain range of temperatures and reverse outside that range. This stuff does not freeze. It simply undergoes a reaction which bonds two types of molecule together to form a cohesive structure. The "normal" rules still apply to both compounds, but the new compound has a higher freezing point. That the reaction to form the new compound is reversible is also nothing new.
Analogy: Water freezes at 0 degrees Celsius, sodium chloride (salt) much higher at 804 Celsius. Add the two together to form an aqueous solution of sodium chloride and it lowers the freezing temperature, contrary to the properties of both substances. Heat it, and evaporate the water off and you end up with solid NaCl.
Sorry, but this has been hyped beyond recognition.
Resistance is futile. Reactance buggers it up.
Warning, this Roland fellow submits (and they get accepted!) stories all the time, which link to his personal blog site. All his posts have the same format. Stop feeding him page views!
I want to delete my account but Slashdot doesn't allow it.
Cookie dough batter turns to solid in oven when heated
Maybe it is because of the loss of water in it...
Secondly, based on the types of compounds in the solution, and the description in the article, the "solid" is probably more of a waxy/jelly sort of substance.
That said, your idea could be made to work in other cases. I wonder if maybe the substance could be altered for use as a variable damping material for suspension or acoustic purposes.
Can someone explain the phrase 'sol-gel'? Does that mean that it become more like a gelatinous subject when heated instead of a more 'solid' solid?
Sols aren't solids. A "sol" is a colloid solution, so is a gel. Without getting too deep into the chemistry, he's basically saying it's a gel.
(Look up 'sol', 'gel', 'dispersion' and 'colloid' for more details)
cyclodextrin? Probably. It's starch.
water? Definitely.
4-methylpyridine? Probably causes cancer. Known to cause damage to the central nervous system. In simple words: Poision.
From Haldex:
Something tells me having hydralic fluid that turns solid when it gets hot wouldn't help a system like thisTo blog is sublime
To a physicist the phase diagram is interesting, because the solid/gel must have a larger entropy than the corresponding liquid. (Remember that you calculate equilibrium by minimizing the Gibbs energy G = H - TS).
Anyway it has been known for many years that some triblock polymers form gels when heated, but perhaps the solid phase of this new liquid is "more solid". Perhaps the news is that the liquid has a larger enthalpy of melting. I don't know
You're talking about a standard 'wet' limited slip differential, or LSD. Wet LSD's have a viscous solution inside that, as the spider gears generate friction by spinning opposite directions, solidifies to unify power delivery from the driveshaft. An open differential allows wheels to spin at differing speeds, usually giving more power to the wheel that's spinning more freely. This is bad in racing. It's also bad for 4wd cars like the Subaru WRX or the Mitsubishi Evolution VIII. Both cars have LSD standard.
The other type of LSD is a clutch-plate type. These can be adjusted for resistance to slippage by arranging the type and order of clutch plates in the LSD. A viscous LSD on the other hand is governed by the properties of the fluid, and is subject to failure under high loads (i.e. the liquid can only take so much friction before it breaks down and loses it's valuable properties). In general practice, for performance and cost, viscous LSD's are used, but for high performance, resilience, adjustability and durability, the clutch type LSD is preferable, but has a significantly higher cost.
That's about all I know about LSD's.
Baking a cake is a chemical reaction, whereas this is a change of the matter's state, which is a physical reaction.
The best option over the above (and a common upgrade) is the fully-mechanical "Torsen" ( torque-sensing ) differential.
Quaife makes one of these. An all-wheel drive car would need three, and at around $1k a pop they aren't exactly cheap, but they have a lifetime warranty.
I don't see how it's the opposite of this at all. Ice-9 just did the same thing that salt does...alter the freezing point of water, although in the opposite direction. Ice-9 was just weird in that the alteration wasn't due to any specific chemical additive, it was due to the molecular layout of Ice-9 itself, and thus it was 'contagious' to any water it touched. It would make that water Ice-9, and so one and so on.
BTW, Ice-9 seems to me a fairly obvious violation of thermodynamics, but I've never heard anyone point that out. Am I just crazy there?
If corporations are people, aren't stockholders guilty of slavery?
It most certainly would melt again after 75C; it's just a hydrogen-bonded organic solid at that point, and hydrogen bonds are weak and only partially-covalent and would easily melt at moderate temperatures.
Solid state to another solid state phase changes also consume energy, which must be the phase change the overclockers use, since the obvious low melting point alloys that liquify around 50 - 60 Celcius tend to conduct - and liquid metal has a way to get into the smallest scratch and turn it into a real crack in a lot of metals (loose liquid metal plus warm motherboard or CPU would be bad). Liquid metals are paticularly nasty to aluminium alloys, so trying to keep it contained in an aluminium jacket inside a heatsink would be a bad idea.
Something like this organic chemical mix near electronics would be a better idea than a liquid metal - but as a solid it would act as an insulator.
Absolutely true. I was just trying to make fun of the very bad headline. The headline was "Science: A Liquid That Turns Solid When Heated", which is not at all interesting.
Also eggs cooking is the water coming out.
Now that is plain b-s. As I said, what happens is that when you add energy (heat) to the proteins, they re-fold and turns into a more stable substance, transforming from a liquid to a firm state.
Just to clearify this so that people dont believe your disinformation. If you boil and egg, in water, with the eggshell intact, you still think you will boil the water away from the "egg", making it firm ? You are utterly wrong, and not informative at all. Even a simple google reveals this, look here or here.
Go back to your cave, troll.
Probable impossibilities are to be preferred to improbable possibilities.
Aristotele
It's a little bit O/T, but there is no point pursuing the liquid-filled beam/column idea - there are much, much better ways (read : both cheaper *and* more effective) of fire-protecting steel.
The basic issue, as you note, is that steel loses flexural strength at an alarming rate when heated. At 500degrees C, the flexural modulus is reduced over 50%, and that's enough to destabilise structures - after which loads get concentrated, and progressive collapse ensues. No need for actual melting.
So: how to keep structural temperatures down. There are a few basic approaches. One, occasionally used when the steel is BIG, is just to rely on Hp/A: if the exposed surface area is small compared with the cross-section, the rate of heating will be acceptaby low. The second is insulation: either a spray-on insulating coating (usually vermiculite-based), encapsulation in concrete, or enclosing with insulative board materials. There are also intumescent coatings, but these are expensive, and so limited to areas where the steel is exposed for aesthetic reasons - lobbies and the like. The third, proposed here, is essentially filling the structure with liquid. But a polymer like this, apart from expense, is never going to abstract enough heat to do any good. There is are only two structures I know of which do this, both exposed tubular structural members: the Cannon Stret office building (Ove Arup & Partners, London, 1973) and the Swiss Re building (Foster & Partners, London, 2003). In both cases the fluid is water with anti-corrosives and a bunch of other chemicals, and is continually pumped. Not cheap, but only water has a high enough specific heat capacity to be useful.
Note further, the point of fire protection is NEVER to save the building. The *only* criterion is to buy time to get people out, and safe. The building can fall, indeed should - after a major fire there will be all sorts of latent damage that could endanger future inhabitants. The two coincided at the WTC: it wasn't just the extraordinary fire load that brought the building down - but the impact which shook loose flaky insulative materials, fatally exposing the (lightweight floor) structure to high rates of heating.
No need; conceptually it's easy enough: each of the aCD moledules gets bent out of shape by the heat, thus exposing more sites for hydrogen bonds to form, allowing the solidification to occurr. Since these molecules are capable of snapping back into the previous shape when cooled, they are therefore storing energy. And so the solid is still in a higher-energy state than the liquid.
"Orthodoxy is unconsciousness" - Orwell