10383994
story
Comments: 153 + - Science: MIT Scientists Make a Polyethylene Heatsink on Friday March 12, @12:10PM
background: url(//a.fsdn.com/sd/topics/topicscience.gif); width:62px; height:75px;
science
background: url(//a.fsdn.com/sd/topics/topichardware.gif); width:64px; height:55px;
hardware
arcticstoat calls our attention to MIT research that has produced a version of polyethylene that can conduct heat away from computer chips. Polyethylene is the most widely used plastic. It's not clear how practical this research is for industrial-scale use, involving as it does an atomic-force microscope. The work is detailed in a paper published in Nature Nanotechnology this month. "The new process causes the polymer to conduct heat very efficiently in just one direction, unlike metals, which conduct equally well in all directions. ... The key to the transformation was getting all the polymer molecules to line up the same way, rather than forming a chaotic tangled mass, as they normally do. The team did that by slowly drawing a polyethylene fiber out of a solution, using the finely controllable cantilever of an atomic-force microscope, which they also used to measure the properties of the resulting fiber. This fiber was about 300 times more thermally conductive than normal polyethylene along the direction of the individual fibers, says the team’s leader..."
Related Stories
Just because I turn down a contract on a guy doesn't mean he isn't going
to get hit.
-- Joey
All trademarks and copyrights on this page are owned by their respective owners. Comments are owned by the Poster. The Rest © 1997-2010 Geeknet, Inc.
Plastic heatsinks? (Score:4, Funny)
Plastic heatsinks, just don't get them near heat!
Re:Plastic heatsinks? (Score:5, Funny)
Parent
Awesome (Score:2, Funny)
What next, a chocolate teapot?
Re: (Score:3, Funny)
Re:Awesome (Score:4, Funny)
Milk or dark?
Why does everything have to be racial for you?! ...oh, I see, I didn't realize that was a profession across the pond. My bad.
...
"by RaceProUK (1137575) [slashdot.org]"
Parent
Re:Heat Diode (Score:4, Informative)
No, they did not.
They built a material that allows heat to flow along one axis. It can go either way through it, but only in that one dimension.
Parent
Is it electrically conductive? (Score:3, Insightful)
Generally, plastic is not electrically conductive. Which makes it good for mounting electronics. But it is also not heat conductive. Which makes it near worthless for mounting.
A non-electric conductive, but heat conductive material would be very useful. Especially if it is CHEAP. It could be used to distribute heat in buildings and not just on circuit boards.
Article is wrong. (Score:5, Interesting)
Before anyone asks, the article is clearly wrong in the statement "The new process causes the polymer to conduct heat very efficiently in just one direction...", the heat moves along one dimensions, in 2 directions.
Re:Article is wrong. (Score:5, Informative)
"The new process causes the polymer to conduct heat very efficiently in just one direction,"
I was thinking, wow, is this even possible? If this is true, I think they've just created a material that could behave like a passive air-conditioner, heater, refridgerator, etc., while using NO power, ever. That alone must be breaking some serious laws of thermodynamics..
"One dimension" or "one axis," would have been more appropriate than "one direction."
Parent
Re: (Score:2)
Re: (Score:2)
Damn straight! And to prove my solidarity...
*whips a cloth off a table* I present my PERPETUAL MOTION MACHINE! Now with plastic cooling for more efficient operation.
Re: (Score:2, Funny)
Re: (Score:3, Insightful)
It wouldn't break any laws of thermodynamics. Say it only allows heat transfer from A to B.
If A is warmer than B, energy (heat) will flow from A to B (from warm to cold), decreasing A's temperature while increasing B's. This process decreases energy while increasing entropy, making it perfectly "legal" according to the laws of thermodynamics.
If B is warmer than A, nothing happens, or, perhaps more realistically, the heatsink now acts as a thermal insulator and only allows a very small amount of energy to go
Re:Article is wrong. (Score:4, Informative)
Yes, I was really intrigued and confused, after reading the line: "The new process causes the polymer to conduct heat very efficiently in just one direction,"
You said:
You connect a heat source to the bottom of a water tank, as it heats water on the bottom, the density of water in vicinity decreases and flow upward in one direction.
He was talking about conduction. You're talking about convection.
Parent
Re:Article is wrong. (Score:4, Interesting)
Parent
Re: (Score:2)
No; you too are wrong. The key missing point is a fiddle. And, possibly, an improbable wager. Then we will know if the material will perform as expected, or if it will run afoul of 'the demon'.
Re: (Score:3, Interesting)
You connect a heat source to the bottom of a water tank, as it heats water on the bottom, the density of water in vicinity decreases and flow upward in one direction.
Yes because that's also the direction of the heat gradient vector. Put a refrigerator at the bottom, and you'll soon find that the transfer of heat is now reversed.
If heat could only transfer from the bottom of the tank to the top, and if the top of the tank was much hotter than the bottom but heat was not transfered to the bottom, then that w
Re: (Score:2)
Very happy to see that this was immediately corrected by this AC comment. Thermodynamics does not allow for heat conductivity in just one direction. If such a material was possible it'll be simple to arrange it in such a manner that entropy spontaneously decreases e.g. having heat conducted one way towards a water reservoir. This accumulated thermal energy could than for instance be used to power a sterling engine making this a second class Perpetuum mobile [wikipedia.org].
Re: (Score:3, Informative)
Just for argument's sake, the jury is still out on 'thermal rectification'. The key is just that you can't ignore certain parts of entropy generation that will exist in such a device. Here's an abstract link from a young professor at UC-Riverside, currently getting a DARPA Young Investigator Award.
Solid-State Thermal Rectification With Existing Bulk Materials
http://dx.doi.org/10.1115/1.3089552 [doi.org]
As long as the system results in a net entropy increase, some versions of the theory say its possible.
Re: (Score:3, Insightful)
Re: (Score:3, Informative)
The little spiny thingy is a perfectly "normal" heat engine in that it exploits a thermal heat difference that is created by an influx of energy from an external source i.e. the photons that heat up the dark side.
The difference with a ideal uni-directional heat conductor is that it allows to create the heat imbalance out of thin air i.e. without putting in additional energy the entropy of the system is lowered. The wikipedia article that I linked to explains this in a bit more detail:
A perpetual motion mac
Re: (Score:3, Informative)
Re: (Score:3, Funny)
"Sign" is in fact how I normally hear it in english.
Re: (Score:3, Funny)
Hmm, it's not often I make a joke that I myself do not get...
Dimension, Not Direction (Score:3, Informative)
I think they mean in one dimension, not direction. The plastic will conduct heat longitudinally a lot better than laterally, but it will conduct heat longitudinally equally well both to and fro. If they ever come up with a material that only conducts heat in one direction (a thermal "diode", if you will) then that solves our energy woes.
Re: (Score:2)
[...] If they ever come up with a material that only conducts heat in one direction (a thermal "diode", if you will) then that solves our energy woes.
And the destruction of the Earth! BWAHAHAHAHA!
Re: (Score:3, Interesting)
Re: (Score:2)
If they ever come up with a material that only conducts heat in one direction (a thermal "diode", if you will) then that solves our energy woes.
Well they would have invented a Maxwell demon at the same time.
that explains the heat sink with the new i7 (Score:4, Funny)
Everybody thought it was plastic, but it was just new technology. Now we just have to wait for an announcement on how to mount those crazy i7's
Re: (Score:2)
Everybody thought it was plastic, but it was just new technology.
Uh Duh. New technology is always plastic, then brushed aluminum, then glass. Rinse and repeat.
Is it a crystal polymer? (Score:4, Interesting)
If all polymer molecule strings are all oriented the same, is it a crystal?
This setup may show interesting optical properties as well. It's amazing research really, with processing matter at that atomic scale control. Being able to buildup matter that precisely will reveal all new dreamed uses. I really hope this will go forward as discovering industrial processes of controlling matter buildup arrangement at an atomic scale in mass-production.
Re:Is it a crystal polymer? (Score:4, Funny)
I don't know if the oriented nature of gel-spun UHMWPE fibers is quite at the same level and provides the same thermal properties as ones made by drawing them out with an AFM cantilever, but they might be "good enough," considering that gel spinning is a scalable industrial production method while cantilever drawing is a "very careful scientist" sort of method.
Well, I have a solution for that. Swap out all the CAPTCHAs on major sites for a webcam peering into an electron microscope that allows a person to draw out the polymer molecules with the cantilever. A week or two, tops, and you'll have someone who's created a bot that can do it perfectly.
Another, similar way is to have Blizzard do the same thing, except using it as a substitute for a CAPTCHA, for every molecule they pull, they get 1 silver piece added to an account of their choice. You'll get the same results, except the bot will speak Chinese.
Parent
Thermal conductivity (Score:5, Informative)
Since neither the summary nor the article has been kind enough to expand on "300 times more thermally conductive than normal polyethylene", I figured I'd look it up.
Thermal Conductivity of some common Materials: [engineeringtoolbox.com]
Polyethylene HD: 0.42 - 0.51 W/mK
Aluminium: 250W/mK
Copper: 401 W/mK
Best case scenario: 153 W/mK or 61% as conductive as aluminium, 38% as conductive as copper. Not exactly impressive for a heat sink
What about therm interface Re:Thermal conductivity (Score:2)
Even if 61% of aluminum axed conductivity would have some uses, a heat sink need to have good interfaces with the heat source and with air or other transfer medium. this heat sink example is really inaccurate. Considering if expectations are for moving heat from one place to another, with limited scatter dissipation, the most efficient method is by having a mechanically moving medium (liquid coolant).
Re:What about therm interface Re:Thermal conductiv (Score:4, Informative)
Parent
Re:Thermal conductivity (Score:5, Informative)
don't forget the rest, though:
Density:
copper: 8.96g/cm3
aluminum: 2.7 g/cm3
silicon: 2.33 g/cm3
AluminumNitride (high thermal conductivity insulating ceramic, k~160to190W/mK): 3.33g/cm3
LDPE and HDPE: 0.92-0.97 g/cm3.
So, you're getting a factor of 2-10x in weight savings. Tell that to a aerospace designer and he'll make it work. It's also a cheap material (well, feedstock's cheap. and normal PE is cheap, especially relative to copper these days). Who knows how expensive this stuff might be if they can make more than single fibers.
Parent
Could Help Cheapen Up Spacecraft (Score:5, Interesting)
The single dimension (not direction) transfer mechanism could also be very useful. If you can ensure that heat will move along only a single axis, you have a bit more freedom in placing sensitive components in and around your conduction paths within your spacecraft. All in all, this could be a really useful material, if it can ever be scaled up for use in industrial applications. Here's hoping.
*crosses fingers*
Of course when plastic is exposed to heat... (Score:2, Insightful)
Competitive, but still not better than (Score:2)
This fiber was about 300 times more thermally conductive than normal polyethylene
Since I couldn't find in TFA the ACTUAL measured conductivity, I turned to the internets:
Using data from the first source I found [engineeringtoolbox.com], at its highest, HDPE's thermal conductivity is 0.51 W/mK. So this material's thermal conductivity in that dimension is about 153 W/mK, or about 3/5 that of Al (250 W/mK), 3/8 that of Cu (401 W/mK), and between 1/6 and 1/15 that of diamond (900–2,320 W/mK, according to wikipedia [wikipedia.org].
So all in all, while this is very fascinating research (and I enthusiastically encourage them t
Re: (Score:3, Informative)
and between 1/6 and 1/15 that of diamond (900–2,320 W/mK)
A very apt comparison since I only use diamond heat sinks for my gaming machines.
Diamond is widely considered to be one of if not the most thermally conductive material available. This comparison was included because for those familiar, it is a handy reference. It was as if, because your arms are too short to touch the ceiling, you believe it doesn't matter how high it is.
On a side note, there actually IS diamond thermal paste available for sale [innovationcooling.com]! Huzzah.
The ability to direct the heat flow can make up for a somewhat lower conductivity for many applications, and can also allow for layouts and applications which wouldn't work with metal heat sinks.
Since the primary issue with metal heat sinks is generally getting the heat wicked off of them, I'd be more apt to consider Finite E
Name? (Score:2, Funny)
Already been done... (Score:2)
May be not as effective, but apparently marginally saleable [cnet.com]. the user experience so far has been terrible but that's the way it is with any new [raymond.cc] technology [com.com].
Now, to make working CPUs out of lead. Solomon's Gold to the rescue!!! Moore's law will be salvaged by modern alchemy!!!
Sure, but... (Score:3, Funny)
Similar to a Niven superconductor (Score:3)
Lovely, another case of life imitates sci-fi. This development reminds me a bit of the superconductors in some of Larry Niven's books (esp. the Ringworld series). In addition to being an electrical superconductor this material was also a thermal superconductor -- and was used as a sort of sci-fi super heatsink on a few occasions. It was mostly represented by ultra-strong threads, and occasionally a woven cloth IIRC.
Re: (Score:2, Interesting)
Re: (Score:2)
No, a Peltier device requires input non-heat energy. No laws of thermodynamics violated. It's just a less efficient heat pump (compared to refridgeration).
Re:Can't it degrade over time? (Score:5, Funny)
make it loose its effectiveness??
They include a tiny wrench to tighten it every so often. The first users are suggesting that you should regularly tighten up effectiveness every 400 hours of running.
MIT researchers are currently trying to counteract this self loosening, you may be able to use loctite [henkelna.com]
Parent
Re: (Score:3, Funny)
I think he meant loose, as in "loose the dogs of war", rather than loosen. It looses its effectiveness on the heat, maybe? And as it loses its effectiveness it can no longer loose its effectiveness.
Re: (Score:2, Informative)
That phrase you're looking for is "let loose the dogs of war".
The verb in that quote is "to let loose", not "to loose".
Re: (Score:2)
Either way, both "let" and "loose" are verbs here.