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: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

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*