It may come as a surprise to some to learn that Teflon, also known as Polytetrafluoroethylene, was in fact created by accident. Its creation in 1938 on April 6 startled chemists at the Chemours Jackson Laboratory in New Jersey, as chemist Dr Roy J. Plunkett was working on alternative refrigerant gases.
Dr Plunkett and his assistant, Jack Rebok, stored the gas they were experimenting (tetrafluoroethylene) in small cylinders where they were then frozen and compressed. Only then when they returned to the cylinders they found that no gas emerged from the cylinder upon releasing the nozzle. As they investigated further, through splitting open the cylinder, they came to find a waxy white solidified concoction, which came to be known as Polytetrafluoroethylene (PTFE).
Following its miraculous discovery, Dr Plunkett then proceeded to run further tests on the curious substance, to learn more about its properties and potential. One of the main factors about Polytetrafluoroethylene that they found most interesting was that it was the most slippery substance known to mankind. This revelation made the substance extremely valuable, pushing forward many other advancements in other areas of study and enabling a whole new world of possibilities. In addition, to polytetrafluoroethylene being one of the slipperiest substances, it also had a number of other useful factors which made it curiously useful. It is non-corrosive, chemically stable and has an extremely high melting point. With such properties, the research was transferred over to the DuPont’s Central Research Department where it was then allocated to a chemist who specialised in polymer research.
Since then, Dr Roy Plunkett has been identified scientifically and academically and takes a place among other well-known inventors, having been inducted into the Plastics Hall of Fame and The National Inventor’s Hall of Fame.
The gas from which Teflon derives from, tetrafluoroethylene (C2F4), is first produced by reacting trichloromethane with hydrogen fluoride (HF) and chloroform (CHCl3) which then produces chlorodifluoromethane (CHClF2). After heating chlorodifluoromethane, you will then acquire tetrafluoroethylene.
Tetrafluoroethylene monomers are then transformed into polymers and this is done by passing the monomers through water and suspending them, resulting in them being polymerised – forged into giant molecules – with the aid and presence of a radical initiator. (1)
The magic of Teflon can be understood further by taking a closer look at the molecule, which is a type of fluoropolymer. Fluoropolymers include the fluorine atom which are responsible for the special qualities Teflon possesses. For every two carbon atoms, there are four fluorine atoms attached throughout the whole molecular structure. The fluorine atoms surround the carbon atoms, creating a protective armour, which then prevent the carbon atoms from reacting when anything comes into contact with the molecule – such as food in a non-stick frying pan.
As well as their restraint from chemical reactions, fluorine atoms also contribute to the low coefficient of friction – low coefficient of friction being a measurement to determine how well two surfaces move past each other as they interact. The more a substance has a low coefficient of friction, the more slippery those surfaces will be. (2)
But you may be wondering, if Teflon is repellent, how can you get it to stick to pots and pans? There are two techniques involved in this process, the first being ‘sintering’, which happens to be very similar to melting. The Teflon is heated at a very high temperature and then pushed down securely onto the surface in which it needs sticking to, however once it has cooled down, it will likely peel away due to its residing fluorine atoms. For this reason, the side of Teflon that needs sticking down will be subjected to an assault of ions under an electric field in a high vacuum. This breaks away many of the fluorine atoms that were preventing the Teflon from sticking down, enabling the surfaces to merge successfully.
Alternatively, Polytetrafluoroethylene can also have its fluorine atoms dispersed using reducing agent chemicals. These chemicals destroy the bond between the carbon and fluorine atoms, enabling the carbon atoms to rejoin with other atoms – resulting in the polytetrafluoroethylene having a stickier surface.