Surface modification and functionalization

The use of atmospheric pressure plasma processes for the cleaning of surfaces as well as the activation of polymer films, wood and wood materials to improve the wettability is already widespread in the industry. The existing and constantly developed technologies at the Fraunhofer IST enable a targeted introduction of functional groups by appropriate process management. As a result, the adhesion of lacquers or adhesives can be significantly improved since the surfaces can be adapted directly to the reactive layer system. On steel, such an adhesive layer can be superior to the traditional surface modifications.

By coating processes at atmospheric pressure, surface tensions can be adjusted specifically. In this way, hydrophilic, hydrophobic and even superhydrophobic surfaces can be realized. Atmospheric pressure plasma processes also enable the production of barrier coatings on flexible substrates, for example to avoid the migration of plasticizers from PVC: With a layer of only 300 nm thickness, the migration can be reduced by 90 percent. With atmospheric pressure plasma processes, silicon wafers, textiles, porous substrates, and objects with 3D geometries can be coated in addition to plastic films and glass substrates.

Modification of wood and wood-based panels

© Photo Fraunhofer IST

Plasma treatment of wood.

As a natural material, wood is exposed to various natural degradation and aging processes, which place restrinction on later improvement and machining operations and thus reduce the scope of applications. Atmospheric pressure plasma treatments successfully address this problem, enabling coating and treatment processes which offer long-term stability and defect-free, safe and efficient coatings and treatments.

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Biofunctional films

© Photo Fraunhofer IST, Falko Oldenburg

Atmospheric-pressure plasma treatment at the Fraunhofer IST: Improved stem cell growth on the surfaces of plasma-coated bags.

Plastics are increasingly being used in medical technology, especially for disposables. For many biological or medical applications however, the various surfaces first have to be modified in an initial step before they can for example be coated in a second step. Disposables often require bio-compatible surfaces in order to promote cell growth on the surface, specifically prevent it or to provide functional groups for the chemical coupling of biomolecules.

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Bonding processes

© Photo Fraunhofer IST, Falko Oldenburg

Coating a wafer with a polyelectrolyte in the spin dryer.

New material combinations are of high importance for innovative industrial processes and products. However, the joining technology is often the weak point of these products. In addition to inadequate adhesion of the adhesives on the materials, migration through the adhesive in particular can significantly reduce the long-term durability of the materials.

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