【英语时差8,16】为什么特氟隆很滑（在线收听）

Why Teflon Is Slippery Teflon is the trademark name for PTFE, a type of plastic. If you own any non stick cookware, then you probably use PTFE on a daily basis. You might not realize, as you fry your morning eggs, that PTFE is one of the most slippery materials that can be manufactured. It’s about as slippery as wet ice. Teflon is chemically similar to another, more common plastic: polyethylene, the material used to make plastic bags and other plastic containers. Chemically, polyethylene is made from long chains of carbon atoms with hydrogen atoms bonded to the sides of the chains. To make Teflon, the hydrogen atoms of polyethylene are replaced by fluorine atoms. It’s the fluorine atoms that give Teflon its slipperiness. Fluorine atoms are physically bigger than hydrogen atoms. Their large size makes them huddle around the central carbon chains in a much tighter formation. This tight formation works like a kind of chemical armor, protecting the carbon atoms which in turn hold the molecule together. This chemical teamwork between carbon and fluorine makes Teflon extremely chemically stable, and it’s this chemical stability that makes Teflon so slippery. Foreign substances, like a frying egg, can find no chemical foothold on the fluorine armor, so they simply slide away. Getting this slippery substance to stick to a frying pan is a bit of a trick. Teflon is broken into a fine powder and suspended in water. The pan is then thoroughly cleaned, then roughened by sand-blasting. The Teflon is sprayed onto the pan and baked, causing it to fuse together and lock onto the roughened surface of the pan. As long as you don’t scratch this protective coating, years worth of fried eggs, melted cheese, burned milk even toffee will slide away effortlessly.