Thursday, 23 June 2011

A better pan by accident

Recently, I moved into a new place.  We were buying some cookware and found an inexpensive pan.  It was smooth and water resistant.  It was made of Teflon.  Most new pans after the 1960's contain Teflon.  Teflon is such a wonderful material particularly because water on the surface of the pan has a contact angle approaching 110 degrees making it incredibly non-sticky.  Also when cooking you do not need to use as much oil because of the oil will also be repelled by the surface of the fluoropolymer.  I think the most amazing thing about teflon is that it was discovered by accident.  Something that we use everyday was discovered by accident. 

In 1941 a scientist by the name of Roy Plunkett worked for a company owned called Kinetic owned by DuPont de Nemoirs and General Electric.  He was researching a new CFC for fridges.  CFC is a fluoropolymer.  One interesting thing about fluoropolymers is that Fluoropolymers share the properties of fluorocarbons in that they are not as susceptible to the van der Waals force as hydrocarbons (like oils). This contributes to their non-stick and friction reducing properties. (I guess you can compare your non-stick teflon pan with a regular pan with oil and compare the contact angle).

The trade name Teflon is polytetrafluoroethylene (PTFE).  PTFE was accidentally invented by Roy Plunkett of Kinetic Chemicals in New Jersey in 1938.  Plunkett checked a gas pressure bottle containing a new CFC refrigerant.  Tetrafluoroethylene gas in its pressure bottle stopped flowing indicating a stuck valve.  Since Plunkett was measuring the amount of gas used by weighing the bottle, he became curious as to the source of the weight as most of the gas should have gone out of the bottle.  After making an explosion proof chamber Plunkett resorted to sawing the bottle apart.  The source of the weight was discovered with a coated waxy white material inside.  After further inspection they noticed it was slippery and water resistant.  It was polymerized perfluoroethylene.  The iron from the inside acted as a catalyst.  It was registered as a trademark under the name Teflon in 1945 and three years later DuPont was producing 900 tonnes of the material.  Later in 1954 a French engineer named Marc Grégoire wife told her husband to coat a pan with this new resin making the first teflon pan later forming the company called Tefal.  A couple of happy accidents makes cooking simpler.