Fluorocarbons have a low London dispersion (induced dipole) force due to the high polarization of the C-F bond. This is responsible for many of the unusual properties of fluorocarbon solvents, particularly high gas solubility and extreme hydrophobicity. It's also just inert, much moreso than chlorocarbons (which tend to be quite toxic).

My undergraduate research project at involved identifying poly-tert-butyl-methacrylate as a polymer with similar hydrophobicity (as measured by the wetting angle) to the fluorocarbons, but I don't think anything ever really came of it. It may be unfavorable for other reasons; I don't remember.

Fluorine forms the strongest bonds to carbon that are available (much stronger than a carbon-carbon or carbon-hydrogen bond, also stronger than carbon-chlorine). It acts like an immovable stub preventing further reactions, which is great for materials like nonstick coatings, but also prevents natural breakdown in the environment.