Surfaces with a low surface energy cannot be coated or glued with a sufficient result. Plasma technology provides solutions to activate effectively any substrate to increase the surface energy so that wettability for adhesives or lacquer can be provided.
Most plastic materials have very low surface energy which in general is lower than the surface tension of the substances which are available for coating. Therefore these substances cannot wet the substrate and will not be able to bond.
Usually the nonpolar character of many plastics is the main reason.
The surface energy of nonplolar plastics can be increased by oxygene plasma activation. The high reactivity of oxygene radicals can create polar links where molecules of the coating material can attach. This process provides wetting by the liquid base substances of the coating.
If oxygene plasma treatment continues etching of the surface starts. In some applications this process may be desired. Etching increases the contact surface of the substrate to provide higher bonding strength.