MIT Scientists Make a Polyethylene Heatsink

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..."

Comments

Plastic heatsinks?

[cbope]

Plastic heatsinks, just don't get them near heat!

Re:Plastic heatsinks?

[idontgno]

All of a sudden Newegg's "counterfeit Intel i7" with its plastic "cooler" makes sense!

Article is wrong.

[Anonymous Coward]

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.

[krnpimpsta]

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,"

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."

Re:Article is wrong.

[srussia]

krnpimsta said:

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.

Re:Article is wrong.

[Rob Riggs]

Read up on Maxwell's Demon. I think the key piece you are missing is that this would be passive heat removal.

Re:Awesome

[RaceProUK]

Milk or dark?

Re:Can't it degrade over time?

[0100010001010011]

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

that explains the heat sink with the new i7

[gbrandt]

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

Is it a crystal polymer?

[La Gris]

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?

[CorporateSuit]

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.

Thermal conductivity

[MartinSchou]

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:
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

Re:Thermal conductivity

[jank1887]

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.

Could Help Cheapen Up Spacecraft

[BJ_Covert_Action]

This material could be another boom material for the spacecraft industry. Some of the heavier hardware on any given space payload is the thermal control system. Using a combination of heat pipes and surfaces coated in various colors of paint for heat control can add a significant amount of weight to a spacecraft. If this material can be added as a thermal layer to the MLI layers that are tacked onto the outside of a spacecraft, it may go a long way in reducing and simplifying the thermal control subsystem of the given payload. In fact, since it is a simple plastic, it should be significantly lighter than various metal contacts and conduction paths within a spacecraft that are used today.

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*

Re:What about therm interface Re:Thermal conductiv

[metamechanical]

The problem with that is that most likely, the interface for the Polyethylene heat sink would be worse than for an aluminum one; The Polyethylene molecule is vastly more complicated than the Aluminum atom, and not nearly as mobile once cast (and would be just as likely to capture little insulating pockets of air, etc.). Even if the Polyethylene molecules on the end could "mold" to the interface, there is not guarantee they wouldn't flop over and become insulating - an Aluminum sink "molded" to the interface wouldn't care, as it's isothermal.

Re:Awesome

[Arthur Grumbine]

Milk or dark?

Why does everything have to be racial for you?!
...
"by RaceProUK (1137575)" ...oh, I see, I didn't realize that was a profession across the pond. My bad.

Re:Heat Diode

[clone53421]

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.