For plasma bonding, plasma activation has to be done first with the intent to alter or improve adhesion properties of surfaces prior to coating, etc. Weakly ionised oxygen plasma is used and several processes take place. Plasma removes surface layers with the lowest molecular weight, at the same time it oxidises the uppermost atomic layer of the polymer. Oxygen radicals (and UV radiation, if present) help break up bonds and promote the three dimensional cross bonding of molecules. Oxidation of the polymer is responsible for the increase in polar groups which is directly related to the adhesion properties of the polymer surface. After having exposed the substrates to the oxygen plasma they are pressed together and then heated to a temperature slightly below the glass transition temperature. This establishes a durable bond between the two substrates.

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Fraunhofer IBMT

Fraunhofer-Institute for Biomedical Engineering
Head of Department Biomedical Microsystems
Dr. Thomas Velten
Ensheimer Strasse 48
66386 St. Ingbert
Germany

phone: +49 (0)6894 980-301
thomas.velten@ibmt.fraunhofer.de
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