Monday, July 28, 2014

Frozen smoke

Translucent, ethereal blue and over 96% air, aerogels are the lightest solids in the world. They’re not 
actually frozen smoke—they’re an artificial material—but the nickname fits. They owe their creation to 
a bet between two chemists, Charles Learned and Samuel Stephens Kistler, in 1931: they wanted to see
 if they could take a gel and replace its constituent liquid with gas, without causing shrinkage. Kistler 
Though aerogels have been improved upon in the years since, his original premise is the same: a 
polymer is combined with a solvent to form a gel, then the liquid is extracted from it and replaced with
 air, hence creating aerogel. The crucial part is that the aerogel must maintain the gel’s structure, so
 they’re solid to the touch and don’t disintegrate.
Aerogels are actually pretty remarkable—they’re the world’s best insulators, being extremely porous 
but low in density; they can withstand explosive damager; and they can support several thousand times 
their weight. Silica-based aerogels are quite fragile, but newer polymer-based ones are extremely strong
 and flexible.

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