The scientific quest behind a very old joke

It's an old joke: How does the teflon stick to the pan? It turns out that the answer involves a relatively long scientific quest to find a smooth substance that can stand the test of time.

When you run your fingers over nonstick pans, they have that ultra-smooth plasticky feel that lets you know why pancakes slide away from them as if they're hostages making a break for freedom. Press your fingers a little harder, and you'll find one of the answers to that oldest of jokes, "What makes the teflon stick to the pan." The teflon is sleek, but underneath you feel a nubbly (that's a scientific term) surface that's far more rough than regular metal pans. That's teflon history right there, because the first thing that got teflon to stick to any pan was a rough, pitted surface.

Nonstick coatings are long chains of fluorine mixed with carbon and hydrogen. The carbon is very important to the process. Carbon and fluorine double bond to each other in rings. It's the strongest carbon bond that there is, and it leaves no chance for anything else to form bonds with the carbon, including any food. The combination of hydrogen, carbon, and fluorine in these polymers has been juggled and re-juggled by scientists for years. Build the chains long and they work like crazy as nonstick substances, but they become viscous - sticking to themselves or each other - and impossible to apply or handle. Keep them too short and they're not really nonstick.

The scientific quest behind a very old joke

The first solution to the problem was to create a surface that almost anything in the world would have to stick to. Manufacturers would either pit the metal viciously or spray on what they called tiny pieces of ceramics and we might call sand, creating a mountainous environment for the polymers. The nonstick coating would get caught in the crags. It would also, with too much scraping, come out of the crags, which is why special rubber spatulas had to be sold to keep the nonstick pans even a little bit nonstick. Nonstick coatings were notoriously delicate. This meant the pans that were supposedly easy to cook with began to require more care than normal pans. Once something burned on, it needed scrubbing to get off. The scrubbing pulled off more coating, which meant more food was going to stick to the pan.

The next incarnation of pans battled this problem with a two step process. They first introduced a primer. This consisted of a version of the nonstick coating that allowed the equivalent of tiny molecular grappling hooks to attach to it. These hooks would also sink into the pitted surface of the pan and hold on tight. Then regular nonstick coating was sprayed on. The polymers cling to each other just fine - it's everything else they have a problem with - and so the two would stick together. As for the ceramic sand, that was transferred to the final layer of the coating, to toughen it up so it wouldn't come off too easily.

The problem with all nonstick coatings is they soften as they heat. If food burns in the pan, the pan is heated too high, or if it isn't loaded with enough food, the sticky coating comes off all on its own. I am a lackadaisical cook, often wandering off to read and coming back to some severely carmelized onions. While other people are more careful, almost everyone has overheated a pan at least once. I'm willing to bet even the best cooks have at least one scrapped up, formerly nonstick frying pan lying at the back of their cupboards and sulking. So the best way to reply to the old joke, if you don't want to get into chemistry, is just saying, "You think teflon sticks to the pan?"

Top Image: Kanko

Second Image: Harecker

Via Straight Dope, RSC, and Discovery.