Plasma – the fourth state of matter as a tool for the surface treatment, explained in the award-winning movie “Plasma – a bright advantage”
Focus of the project IP4Plasma project are innovations in the area of surface treatment using cold ambient pressure plasmas to be demonstrated in new processes for the production of medical products including an advanced tuberculosis test and new types of wound dressing. The type of plasma, to become more specific, is a dielectric barrier discharge (DBD) plasma. Such a plasma has been for decades conventionally applied in the so-called corona treatment of plastic film materials before processing steps such as printing or laminating. Treatment is achieved by contacting the polymer surface with the plasma with its reactive components (you may refer here to the previous section ”What is a plasma?”) These react with the polymer and thus modify its surface by changing its chemical and physical nature, e.g. by the attachment of chemical groups. The result may be improved wettability of a polymer film. This is needed, for example, for printing advertisements on plastic bags using aqueous inks. Without the plasma treatment the ink would be easily wiped away on contact with e.g. sweaty hands. Examples for the equipment used can be found e.g. on the website of SOFTAL Corona & Plasma GmbH Without treatment there would be no printability at all or the inks would be wiped off on the slightest contact with the hands.
The potential scope of the ambient pressure plasma technology does, however, extend far beyond the just mentioned and industrially well-established applications, where the surface is treated whole area and without depositing a coating. The technology allows, for example, to apply the plasma treatment selectively on certain surface areas. This is called an area-selective or local treatment.
Also, a so-called film-forming agent (sometimes called “precursors”) may be added to the plasma gas. Under properly chosen conditions this leads to the deposition of a coating on the treated material.