One of the most unstanding bernefits of completely fluorinated hydrocarbons like PTFE is its almost complete resistancy against any chemical attack. This characteristic however also prevents almost any chemical surface treatment. Moreover PTFE has the lowest surface energy of all solid materials, so that no wetting by adhesives, paintings or coatings takes place. Therefore it is considered to be practically impossible to glue, print or paint these substrates.
Even etching in an oxygene plasma does not improve adhesion to a PTFE surface
Even though also PTFE can be Plasma treated so that adhesion is provided.
This Plasma treatment process takes place in an hydrogen plasma. It can be considered to be an activation or an etching process.
The essential reason for the chemical resistancy of PTFE is the extreme stability of the C-F- bindings, which prevents the reaction with any other atom or molecule. Active species of the plasma however even crack C-F- bindings. Hydrogen -ions, -radicals and stimulated atoms join the Fluor-radicals which only exist for very small intervals of nanoseconds to form HF-molecules. Consequently unsaturated Carbon-bindings remain for restricted time, however at least for minutes, so that adhesion of molecules of adhesive mölecules is enabled.