
Inside tiny tubes, water turns solid when it should be boiling - dkarapetyan
http://news.mit.edu/2016/carbon-nanotubes-water-solid-boiling-1128
======
cyberferret
Always enamoured of the properties of water - there is still so much to learn.

I remember in my flying school days we were learning about microscopic drops
of water which, at altitude, would retain their liquid state below 0degC and
only freeze when coming into contact with metal or another foreign object.
Biggest cause of icing on wings, intakes and carburettors (on piston
aircraft). Because the molecules were still in liquid form, radar cannot
identify it as an icing hazard...

Pretty much the opposite end of the scale from this article.

~~~
FreeFull
A fun experiment to try is using your freezer to supercool water inside a
plastic bottle, and then making it suddenly freeze by smacking the bottle.

~~~
cr0sh
We did something like this in high school as part of our chemistry class. We
supercooled the distilled water using a salt/ice bath, taking it well below
freezing (in a test tube). Then we introduced a "seed" (don't remember if it
was a chip of ice, or a bit of sand, or what) - and watched it "freeze"
instantly. I'd have to look at my notes to know what the experiment actually
was for, how it was conducted, lab notes, etc - because there was a point to
it all (not just as a demonstration of super-cooling and freezing)...

~~~
Declanomous
That reminds me of a really cool experiment we did in chemistry. You can
create anice packs" that are basically a super-saturated solution that
precipitates when you snap a little trigger in the corner of the pouch,
creating an endothermic reaction. It was really awesome, and I definitely
remember a lot more from experiments like that then I do "titrate [x] in to
[y] and take notes" experiments.

~~~
eth0up
Has me thinking of the dangers of drinking vodka outdoors in Siberia, in the
winter. Of course any ill effect of the vodka might be considered mercy, in
such conditions.

~~~
0xdeadbeefbabe
It might make you need to use the bathroom outdoors in Siberia.

~~~
eth0up
A Russian born in Siberia once told me how do so (v2), in Siberia:

"With a stick in each hand...", he said, "one for the dogs, and one for the
turd."

Back to supercooled water, here's a _cool_ demonstration:
[https://www.youtube.com/watch?v=fSPzMva9_CE](https://www.youtube.com/watch?v=fSPzMva9_CE)

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james_a_craig
I wonder if the forced phase-change the confinement causes applies to other
contexts? Could we use a similar trick to force superconductive materials into
their low-temperature superconductive phase at higher temperatures? (Repost of
the same comment from the other thread about the same paper)

~~~
inlineint
I'm by no means an expert, and I may be wrong, but I personally don't think
that it's possible to achieve superconductivity at room temperature and normal
pressure using this approach at the current state of the art.

If you take a look at the phase diagram of the water [1] you could notice that
the pressure required to crystallize water at temperature near 105°C is
something near p_freeze = 2.5⋅10^9 Pa. However, the water is inside of the
nanotubes of radius r = 0.5⋅10^(-9) m (the article says about the tubes being
of diameter 1.05 nm). Such small radius creates significant surface tension
(the same force that allows soap bubbles to exist) which is expressed by
equation [2] as Δp = γ/r. According to [3] the surface tension coefficient for
water at 105°C is γ = 58⋅10^(-3) N/m, so Δp ≈ 1.2⋅10^8 Pa. The required for
crystallization and the actual pressures differ in just one order of
magnitude.

But the reasoning above used the macroscopic physical laws, and of course one
could expect deviations from them when thinking about diameters as small as 4
water molecule diameters. Of course there is still no theoretical model that
describes this configuration and calculates exact values of p_freeze and Δp
precisely for it. But such model don't have to change the orders of magnitude
in the problem, just estimate factors of order of 1, and we could use rough
intuition gained previously about the process even without such model.

So if you try to apply these intuitions to the superconductivity you
immediately meet difficulties because all known superconductors are in solid
state, not liquid. It could be overcome by putting it to the nanotubes in
liquid state and then letting it crystallize. Let's assume that this is
possible. Evidence [4] suggests that to get a superconductor at high
temperatures it requires to have pressure of order 10^11-10^12 Pa. This
pressure is two orders of magnitude higher than the one required to freeze
water at 100°C. That means that surface tension coefficient in such material
should be two orders of magnitude higher than in liquid H2O to create pressure
of order of magnitude required for phase transition to superconducting state.

I wasn't able to find data about surface tension in superconducting materials
like like H2S mentioned in [4], but I doubt that it is 100 larger than surface
tension in water. And it is impossible to significantly increase pressure by
decreasing radius of tubes because this radius is already of order of
molecules size. So I don't think that it is possible to get high temperature
superconductors at normal pressure and room temperature using nanotubes and
already known superconducting materials.

[1]
[https://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Ph...](https://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Phase_diagram_of_water.svg/700px-
Phase_diagram_of_water.svg.png)

[2]
[https://en.wikipedia.org/wiki/Surface_tension#Surface_curvat...](https://en.wikipedia.org/wiki/Surface_tension#Surface_curvature_and_pressure)

[3]
[https://srd.nist.gov/JPCRD/jpcrd231.pdf](https://srd.nist.gov/JPCRD/jpcrd231.pdf)

[4]
[https://arxiv.org/pdf/1506.08190v1.pdf](https://arxiv.org/pdf/1506.08190v1.pdf)

------
saganus
“This gives us very stable water wires, at room temperature,” he says.

Even the name is cool: "water wires".

So beyond fiber optics we could have water wires? This should help photonics
researches make a (faster) computer with light, right?

~~~
sho
> water conducts protons at least 10 times more readily than typical
> conductive materials

Protons, not photons!

~~~
choonway
Shouldn't it be phonons?

~~~
drbw
No - they mean hydrogen ions, which are just bare protons.

~~~
dnautics
well no single proton actually makes it all the way across, so it is a phonon!

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karmacoda
As a non-physicist I was thinking the molecules become jammed, immobilised
upon expansion; for want of a better analogy a swollen foot in a shoe, no more
wiggle room. But the article says that the solid water does melt at even
higher temperatures.

~~~
geon
Kind of like this?
[https://www.youtube.com/watch?v=aI0euMFAWF8](https://www.youtube.com/watch?v=aI0euMFAWF8)

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barisser
1nm carbon nanotubes... I doubt these can be produced at macroscopic scale.

Moreover the difference between 1.05 and 1.06 nm drastically affected freezing
point. I don't think these can be built, en masse, to such precision.

~~~
jessriedel
> Moreover the difference between 1.05 and 1.06 nm drastically affected
> freezing point.

I think the author might have misread something. The Van der Waals radius of a
carbon atom is only 0.17 nm, so the radius of a single tube can't vary in
steps of 0.01 nm. Maybe this just referred to the average tube radius?

~~~
tgb
Hmm. A tube is composed of many carbon atoms in a ring. Add one more atom, you
increase the circumference by 0.34nm but the radius only by 0.34/2pi=0.054nm.
So still looks infeasible.

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civilian
I understand that this requires carbon nanotubes, but I'm still excited that
we're one step closer to Ice-9

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avian
Reading this reminded me of polywater.

[https://en.wikipedia.org/wiki/Polywater](https://en.wikipedia.org/wiki/Polywater)

~~~
mannykannot
I get the impression that these results are at least thermodynamically
plausible, unlike polywater.

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kazinator
Also: if you confine water to a single H2O molecule, you can make the entire
phase phenomenon go away!

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aexaey
Interestingly, there seem to be an established names for flat/planar/2D
inclusions:

[https://en.wikipedia.org/wiki/Intercalation_(chemistry)](https://en.wikipedia.org/wiki/Intercalation_\(chemistry\))

As well as for point/0D inclusions:

[https://en.wikipedia.org/wiki/Clathrate_compound](https://en.wikipedia.org/wiki/Clathrate_compound)

..but not for what this article describes, which appear to be linear/1D
inclusions.

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kafkaesq
Lookout -- they're that much close to discovering ice-nine:

[https://en.wikipedia.org/wiki/Ice-nine](https://en.wikipedia.org/wiki/Ice-
nine)

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ceejay

      "electrical and thermal properties of ice while remaining stable at room temperature"
    

This sounds pretty amazing. My first thought was there has to be some sort of
application toward air conditioning. However, then I started thinking that an
even better place to start would be to find ways to utilize this in clean
energy. The scale / complexity of production could probably be a non-starter,
but (just as an example) if I can put ice into a body of water and more or
less guarantee it will never return to water form, at a large enough scale it
probably could have hydro-electric applications.

~~~
delinka
I'm not sure how "non-defrosting water" gets us to "hydro-electric
applications." Can you elucidate?

~~~
ceejay
Forgive me if the idea appears somewhat naive. Please correct me if I'm wrong
about this but, given that the "frozen" water exhibits thermal properties of
ice, in theory couldn't a closed system be built to generate electricity given
the constant displacement of water running through the system. By taking
advantage of the constant cycle of temperature variations within the system?

EDIT: Just looked it up, it appears difference in weight between 4 deg C and
21 deg C (1 ft^3 of water) is a little more than 1/10th of 1 lb.

[http://water.usgs.gov/edu/density.html](http://water.usgs.gov/edu/density.html)

~~~
kriztw
It sounds like you are proposing a perpetual motion machine, which cannot work
because of the laws of thermodynamics (see
[https://en.wikipedia.org/wiki/Perpetual_motion](https://en.wikipedia.org/wiki/Perpetual_motion)).

~~~
ceejay
Don't get me wrong. I agree with the laws of thermodynamics :) , but just like
we exploit a "closed loop" / "seemingly perpetual" system between the moon and
the oceans, or flowing rivers, couldn't there exist other "closed loop"
systems? After all, on the scale of a human life that closed loop system
(between moon and oceans) is, for all practical purposes, perpetual.

~~~
pjc50
The water cycle is not "perpetual": it depends on input from the sun.

The tides are not "perpetual": they depend on gradually taking energy from the
orbit of the moon.

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haikuginger
Microfuidics have a lot of interesting potential applications; $SPOUSE works
on using them for point-of-care diagnostics, also in the MIT ChemE department.

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micaksica
> “All bets are off when you get really small,” Strano says. “It’s really an
> unexplored space.”

I'm going to assume that this pun was intentional by Strano, and sadly I think
it's gone past everyone who's in awe of the actual finding.

~~~
acbabis
I don't understand

