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Modern non-stick frying pans use a mixture of titanium and ceramic that is sandblasted onto the pan surface, and then fired to 2,000 °C (according to Wikipedia).

Can anyone explain (at the molecular level), Why cooking materials do not stick to these surfaces?, a hydrophobic effect would work if the food was mainly water but these surfaces are not affected by oily materials either.

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up vote 4 down vote accepted

I don't own any such pans, but I understand that they use a ceramic coating on top of a titanium base. The non-stick behaviour is down to the ceramic and not the titanium.

I'm not sure anyone knows exactly what causes food to stick to pans, and I suspect it's lots of different mechanisms. Anything that contains protein probably sticks because amino acids will co-ordinate metal ions, so proteins bond to metal pretty easily.

Making a surface non-stick is basically a matter of making it unreactive and/or non-polar. That way the food can form neither chemical nor hydrogen bonds. Bare metals are generally very reactive (does food stick to a gold frying pan?) and therefore a poor choice. By contrast PTFE is very unreactive and indeed non-polar, so there's no easy way for the food to adhere to it. Ceramics are pretty inert, and indeed they're commonly used in industry because of their inertness. Their only weakness tends to be reaction at low pH, but this probably isn't an issue for the sorts of pHs found in food. Just don't try to cook sulphuric acid!

Using ceramics in cooking is hardly new. Glazed ceramic cooking pots date back millenia. However ceramic pots conduct heat poorly and they're fragile. Presumably the advance in non-stick pans has been to find a way to bond a ceramic coating to metal without it flaking off.

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Excellent detailed answer, thanks. –  Gearoid Murphy Nov 4 '12 at 15:30
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I seem to be specialising in answering questions about cooking. Maybe we need a cooking tag :-) –  John Rennie Nov 4 '12 at 15:36
    
Hello John, I've a doubt - Aren't silicone resins used now for non-stick pan coating..? because that's what I've learned in high-school..! (back a year) :-) –  Waffle's Crazy Peanut Nov 5 '12 at 12:42
    
I'm pretty certain that my Mum has some silicone baking trays. I didn't know silicone derivatives could be used on pans. I'm surprised it has enough thermal stability. –  John Rennie Nov 5 '12 at 14:05
    
@John, alteratively you could hand around on Cooking.SE some. They do have questions that call for a physicist from time to time. Indeed, my best two answers over there are physicy. –  dmckee Nov 5 '12 at 17:05
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