Plasma activation

Plasma activation (or plasma functionalization). It is done with the intent to alter or improve adhesion properties of surfaces prior to coating, painting, etc. In most cases, the surface in question is surface of a polymer material and weakly ionised oxygen plasma is used.

Surface activation is a result of following processes:

Removal of weak boundary layers. Plasma removes surface layers with the lowest molecular weight, at the same time it oxidises the uppermost atomic layer of the polymer.

Cross-linking of surface molecules. Oxygen radicals (and UV radiation, if present) help break up bonds and promote the three dimensional cross bonding of molecules

Generation of polar groups. Oxidation of the polymer is responsible for the increase in polar groups which is directly related to the adhesion properties of the polymer surface.