Teflon, used for non stick coatings, is a polymer of

Explanation

Every hydrogen of ethene is replaced by fluorine, and the resulting carbon to fluorine bonds are so strong and the surface so non polar that the polymer is chemically inert, heat resistant and extremely slippery. This is why teflon is used in cookware and in laboratory taps and seals. Chloroethene gives PVC and styrene gives polystyrene.