Regeneratable long-term activation on transparent plastics

The industrial research institute Innovent, Jena, German, has developed a nanometer thin coating that creates a hydrophilic, long-term resistant surface regardless of the type of plastic material used. When painting on plastic surfaces, the low surface energy of the materials quickly leads to technological limitations. The poor adhesion on plastic surfaces can be improved by hydrophilization. Established processes are the activation of surfaces by plasma or flame treatment. The effect of these pretreatments is strongly dependent on the plastic used and reversible after a short time. The subsequent further processing of the plastic surfaces should therefore take place as quickly as possible. Further improvements in the long-term resistance of surface properties have now been achieved through the development of plasma coatings at atmospheric pressure. The deposited transparent silicon oxide thin films still exhibit hydrophilic wetting properties after up to six months of storage. After a special refreshing in an aqueous environment, it is possible to reduce the water contact angle by up to 30° again as a measure of wettability, even with coatings more than one year old. These significant results were demonstrated using PC and PMMA as examples. As an additional side effect, the SiOx thin film has an anti-reflective effect on both transparent polymers.

Author(s): Ke

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