An empty gas cylinder wasn't empty — it was coated in the first non-stick plastic

In 1938, DuPont chemist Roy Plunkett opened a cylinder of tetrafluoroethylene gas expecting it to hiss out under pressure — instead nothing came out, though the tank still weighed full. He sawed it open and found the gas had spontaneously polymerized into a waxy white powder that nothing would stick to. DuPont patented it in 1945 as Teflon.

— Sam Kean, The Disappearing Spoon — chapter on the halogens, 2010
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