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Comment by olivermarks | Hacker News Reader

'...the device can heat from 300C to 1500C in 30 seconds, he says." Furthermore, the ultrathin property allows easy heat transfer from the metamaterial to the material needed to be heated, such as water, and so could be used to desalinate seawater, for instance'.

If this is accurate that has great value and utility

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Remember that temperature does not indicate energy. A graphene layer is a tiny amount of mass per surface area, so a absorbing single (small-c) calorie of energy would be enough to raise a patch of graphene to outrageous temperatures- but, you'd still only be able to get that single calorie back out, which wouldn't do much to a liter of seawater or whatever.

For that matter, it doesn't seem like they specify under what conditions this heating is taking place. Fire a high-powered laser at something and you might see that behavior in a variety of materials.

I was thinking huge areas of graphene but point taken, I was just reading up about graphene after reading the post...

fun science experiment... fill a large beaker halfway with water and sprinkle a thin layer of powdered, activated charcoal (carbon/graphene) over the surface, cover the top of the beaker with saran wrap and place outside in the sun at midday. the temperature of the charcoal will get much warmer but not much else

Isn't that because it is fairly hydrophobic so it doesn't make good contact with the water?

yeah, there have been previous papers on creating membranes that wick some of the water up to be heated, and turned into vapor, but not so much that it cools down the carbon layer.

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