is a chemical process that removes the fluorine atoms from the surface
layer of the fluoropolymer. This surface
layer is so thin; it is most conveniently measured in Angstroms. Once the fluorine atoms are removed, the carbon atoms left behind in the etched polymer quickly forms temporary bonds with atoms from the air
, such as oxygen, nitrogen, and sometimes even hydrogen. Since these bonds are much weaker, the carbon atoms are still reactive, reducing the surface
lubricity and allowing for a more bondable product. Because of the loss of carbon-fluorine bonds, once the surface
of your fluoropolymer is etched, the properties of the etched area are changed. One will no longer have the lubricous and low energy surface
that is expected from a fluoropolymer. Instead, one will have a wettable, bondable, frictional surface
upon which to glue, mold, or print onto your product.
Etching will only affect the chemistry
of the surface
with which it comes in contact. The properties of your fluoropolymer are kept intact not only underneath the etched surface
, but on the entire remaining unetched surface
as well, meaning that the etched product’s bulk properties are unaffected by this process.
The results of the etching are not permanent, however. If left unused for long periods of time or stored incorrectly, the etched part regains its initial low bondability.
Chemical treatment of PTFE is almost impossible because PTFE is completely inert against chemical attack of all conventional organic solvents, acids and lyes. The only chemical substance
to attack PTFE is a solution ao alcaline metals which is able to etch
PTFE forming alcaline fluorides. The process is very dangerous and all substances involved are extremely hazardous.
A perfect alternative
is plasma treatment by hvdrogene used for process gas in a low pressure plasma. Hydrogene ions and radicals react with fluorine atoms to Hydrofluoric acid and leave unsatturated carbon bindings which provide perfect links for organic molecules of coating substances.
The chemical etching process causes a reaction between the fluorine molecules in the surface
of the material and the sodium solution. The fluorine molecules are stripped away from the carbon backbone of the fluoropolymer, which leaves a deficiency of electrons around the carbon atom
. Once exposed to air
, hydrogen, oxygen molecules and water vapour restore the electrons around the carbon atom
. This results in a group of organic molecules that allow adhesion to take place.