Monday, 15 October 2012

My Surface Energy Reducing Non-Stick Pan: A Salute to Teflon

I love cooking.  Cooking to me is the Jeux de vie.  Lately, I have been learning how to cook French and Italian food.  Both require either butter or a lot of olive oil.    In old times part of the reason people use oil or butter was partly for taste and partly to make the things you are cooking not stick to the pan.  If you are cooking pasta and you do not add oil the hydrophobic parts of the starch will make the pasta stick together.  If you are cooking eggs likely part of the eggs will be stuck to the pan.  This is mostly evident if you are using an old cast iron pan.  People know that you need much more oil in order for the food not to stick to the pan.   The non-stick pan was invented for this purpose.  To make eggs and everything else not stick while requiring the need for less oil and fats.  The non-stick pan also saves a little time and frustration when cooking and cleaning up afterwards. 

Tefal Pots and Pans

Around seventy years ago non-stick pans were not available.  The main part of the non-stick pan did not exist.  At the time there was no thermoplastics (or none that I am aware of) that existed to reduce the surface of energy of pans.  So butter, oil, wax and spam were widely the best way to do this before teflon was invented.  The interesting thing about teflon was it was a nice accident.

This is described in Plunkett's own words:

 'On the morning of April 6, 1938, Jack Rebok, my assistant, selected one of the TFE cylinders that we had been using the previous day and set up the apparatus ready to go. When he opened the valve — to let the TFE gas flow under its own pressure from the cylinder — nothing happened. Jack called me over and asked whether we had used all the TFE from that cylinder. I said, I don't think so. We both tinkered with the valve a bit, and then thinking it might be stuck or closed in some way, we disconnected the cylinder from the line and pushed a wire through the valve opening. Still no TFE came out, although the weight of the cylinder showed that there was material inside. We were in a quandary. I couldn't think of anything else to do under the circumstances, so we unscrewed the valve from the cylinder. By this time it was pretty clear that there wasn't any gas left. I carefully tipped the cylinder upside down, and out came a whitish powder down onto the lab bench. We scraped around some with the wire inside the cylinder — or maybe I tapped it — I don't remember which — to get some more of the powder. What I got out that way certainly didn't, add up, so 1 knew there must be more, inside. Finally, more out of curiosity I suppose than anything else, we decided to cut open the cylinder. When we did, we found more of the powder packed onto the bottom and lower sides of the cylinder.'

 Sometimes a happy accident happens. I called the guys at Dupont one time and they told me a similar story.  It is quite funny but science is sometimes an accident.  Without Fleming leaving his bread out on the table we would not have had penicillin.  However, the people making these ´´discoveries´´ like Plunkett or Fleming need to fulfill to secondary need that it is an actual discovery.  So with Plunkett´s discovery that this white stuff was actually a valuable he could reproduce it in the lab and help to make DuPont billions and billions of dollars.  Dupont would go on to use it for a number of applicatons it thought about.  The material allows water and oil to not absorb due to the low surface energy of teflon and the surface tension of water and oil is too high to stick to the pan.  If one were to put water on a teflon pan you would see a surface energy creates nearly a 180 degree angle between the air-water and surface of the teflon  coated pan.  Put another way the water molecules are more attracted to themselves than to the teflon molecules in the pan. 

Other inventions for a great material come from the public.  Fourteen years after Plunkett´s discovery of teflon a French engineer named Marc Gregoire created the first pan (likely he knew that the French tradition of using a lot of butter for cooking was not healthy).  Actually his wife urged the engineer to use the material he was using on fishing tackle on her cooking pans.  That company called Tefal is still around today.  The first US made Teflon pan had less success as the ´´The Happy Pan´´ (not really sure why a pan should be happy but it is some 1950´s bad marketing gimmick).

So due to a few industrious people by accident and coincidence made teflon pans.  Now I am going to use my Tefal pan to cook some pancakes.