The first time I saw a Teflon-covered pan, when I was four or five, I thought it was magic. Now that I cook, I’m even more impressed by non-stick surfaces.
Teflon was discovered by accident by Roy J. Plunkett, 27, a DuPont scientist who was trying to develop a new chlorofluorocarbon (CFC) for use as a refrigerant by reacting a gas called tetrafluoroethylene (TFE) with hydrochloric acid. He’d prepared 100 pounds of TFE in pressure cylinders, which, for safety reasons, he stored in dry ice.
On the morning of April 6, 1938, Plunkett’s assistant, Jack Rebok, opened the valve of a canister of TFE–and nothing came out. They weighed the cylinder. The gas was still inside, but it wouldn’t come out.
Plunkett, frustrated, took off the valve, turned the canister upside-down, and shook it. Some flecks of white powder floated out. Intrigued, Plunkett and Rebok sawed open the canister and found a smooth, waxy white coating lining it. The substance wouldn’t char or melt and seemed to be impervious to solvents, moisture, sunlight and mold and fungus.
Apparently the cold and pressure had caused the molecules of TFE to join together in long chains, or polymerize, so Plunkett dubbed the new stuff polymerized tetrafluoroethylene (PTFE), and patented it for the company in 1941.
DuPont continued experimenting with PTFE, trying to figure out how to produce it commercially. The Second World War provided a boost: PTFE was used in the nose cones of proximity bombs and in airplane engines, even though it cost $100 a pound. In 1944, DuPont trademarked PTFE as Teflon.
It wasn’t easy to produce. Early batches tended to have widely differing properties, and making it required equipment to withstand higher temperatures and pressures than ever before. Turning it into useful articles was problematic, too. Its melting point was so high it couldn’t be molded or extruded, and as for bonding it to something else–how do you bond the greatest non-stick surface every created?
Fortunately, researchers found several ways. In granular form, Teflon could be compressed into blocks that could be machined; it could blended with hydrocarbons and cold-compressed to coat wires and make tubing; or it could be blended with liquid and turned into enamels that could be sprayed or brushed, then baked into place.
The first commercial Teflon plant opened in 1950. Most of the output went to commercial applications: tape, sheets of insulation, gaskets, valves, etc. Bread manufacturers used Teflon-coated rollers; candy factories used Teflon-coated conveyer belts.
The first Teflon-coated baking pans appeared in the 1950s. Concerned about safety, DuPont proceeded very slowly with the development of Teflon-coated pans for stovetop use; meanwhile, in France, an engineer named Marc Gregoire figured out how to affix a thin layer of Teflon to aluminum. His wife, Colette, suggested making cooking pans that way. Starting around 1955, Marc made coated pans in their kitchen and Colette peddled them on the street. In 1956 the couple formed the Tefal Corporation in 1956 and opened a factory.
The French government soon declared Teflon safe, which spurred DuPont to seek similar approval in the U.S. Then Thomas G. Hardie, who admired French culture and was familiar with Tefal, began importing Tefal pans, marketing them under the name T-Fal. They were a hit, DuPont finally got in the act, and by the early 1960s, non-stick cookware was everywhere.
Today Teflon is used to insulate tablecloths and carpets, coat steam irons and toughen nail polish, and in pacemakers, dentures, medical sutures, artificial body parts, printed circuits, cables, space suits and Gore-Tex, the favorite fabric of campers and skiers.
But now researchers may have gone Teflon one better.
Jan Genzer, a professor at North Carolina State University, has discovered (by accident) a way to make non-stick surfaces even slipperier. The substance being coated is stretched slightly and then coated with a polymer (Teflon, for instance). When the tension is released, the surface snaps back into place, pulling the polymer molecules together so tightly nothing can bond to them.
Teflon, slick as it is, has irregularities at the molecular level. This new method eliminates those irregularities. Devices coated with these friction-free polymers can bang against each other without scratching. Liquids won’t coat them, and even solvents designed to dissolved the polymer can’t affect them.
Genzer is currently testing the coating’s long-term stability and resistance. If all goes well, within five or six years we could see a whole new wave of non-stick devices, ranging from airplane wings that never ice up to medical implants that never deteriorate.
Pretty slick, eh?