The most notable characteristic of polytetrafluoroethylene (PTFE, DuPont's Teflon) is that nothing sticks to it. This complete inertness is attributed to the fluorine atoms completely shielding the carbon backbone of the polymer.
If nothing indeed sticks to Teflon, how might one coat an object (say, a frying pan) with PTFE?
It has to be so common a question that the answer is actually given in various places on Dupont's own website (Dupont are the makers of Teflon):
“If nothing sticks to Teflon®, then how does Teflon® stick to a pan?"
Nonstick coatings are applied in layers, just like paint. The first layer is the primer—and it's the special chemistry in the primer that makes it adhere to the metal surface of a pan.
And from this other webpage of theirs:
The primer (or primers, if you include the “mid coat” in the picture above) adheres to the roughened surface, often obtained by sandblasting, very strongly: it's chemisorption, and the primer chemical nature is chosen as to obtain strong bonding to both the metal surface. Then, the PTFE chain extremities create bonds with the primer. And thus, it stays put.
Before putting Teflon on a pan, the pan is scratched hardly leaving some tiny holes where the hole opening is smaller than the hole inner size (like a bottle). When Teflon is cast into that, it physically can't get out. That's also why when you scratch a Teflon pan, things start sticking to it.
they spray a primer first on the substrate to be coated (the frying pan) , then they spray the fluoropolymer powder on it. the primer is the tricky part. i think the idea is they make another copolymer of ptfe and another monomer that dont have all its C atoms saturated with F. this copolymer sticks to ptfe because it contains ptfe and at the same time can stick to other substances more readily vs pure ptfe polymers due to other c atoms not fully saturated with Florine.this copolymer is mixed with a polyamide or polyimide or other forms of plastic that would stick after melting to the frying pan. so to sum it up . the polyamide plastic sticks to the aluminum of the pan. then the copolymer of ptfe and perfluoro polymer sticks to the polyamide and finally the top coat of ptfe is applied over that copolymer and sticks to it . the idea here is this copolymer that is half ptfe and half perfloropolymer that sticks to ptfe above and other adhesives below. its a gradient from sticky substance up to a completely non stick pure ptfe. at least this is what i understood from reading some of the patent information about the primer used by chemours(dupont). for more detailed information you can refer to these patents.
