Teflon is the Dupont trademark name for polytetrafluoroethylene (PTFE). The polymer is best known as a non-stick coating on pans and other cookware, even thought its main use is actually as an electrical insulator for wires and cables. It’s also found in lubricants, Gore-Tex, medical equipment, fiberglass, and stain repellents. Here is look at how Teflon works and how manufacturers get it to stick to pans.
How Teflon Works
The secret to Teflon’s slipperiness lies in its composition and chemical bonding. Teflon is a polymer of tetrafluoroethylene subunits. Basically, it’s a long chain of carbon atoms, with fluorine atoms attached to the chain. All the exposed fluorine atoms make the polymer extremely hydrophobic (water-repellent). The polar covalent bonds between the carbon and fluorine atoms are strong enough that the fluorine resists interaction with any other atoms or molecules. This makes Teflon corrosion resistant and gives it one of the lowest coefficients of friction of any solids.
If Nothing Sticks to Teflon, How Does It Stick to Pans?
If Teflon is so slippery, you may wonder how it sticks to pans in the first place. There are two methods:
- Sintering is one way to get Teflon to stick to pans. The first step is sandblasting or otherwise roughening the pan surface to forms tiny holes in the metal. Applying Teflon to the prepared pan allows the polymer to seep into the nooks and crannies. Finally, applying an additional layer of Teflon, pressing it onto the surface, and heating it (sintering) completes the process. The second layer of Teflon adheres to the first layer because the one thing Teflon sticks to really well is more Teflon.
- Physical and chemical treatments help PTFE stick to pans. One method involves ion bombardment of the side of the polymer meant to stick to the pan. The treatment breaks chemical bonds and removes fluorine atoms, so the sticky carbon atoms adhere to the metal. Another method chemically modifies the Teflon surface. A reducing agent removes the fluorine atoms, leaving unsaturated hydrocarbons. These carbon atoms lack electrons, so they readily bond with metal. As with sintering, it’s easy to apply additional layers of Teflon once it has stuck to the pan.
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