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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: POSTER: Polymer Physics
CPP 8.35: Poster
Monday, March 26, 2007, 16:00–18:00, Poster B
Surface functionalization by ultrathin plasma polymer coatings: From partial coverage to closed films — Jakob Barz1,2, Michael Haupt1, Christian Oehr1, and •Achim Lunk2 — 1Fraunhofer IGB, Nobelstr. 12, 70569 Stuttgart — 2Institut für Plasmaforschung, Universität Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart
Plasma processes based on different monomer precursors are successfully applied to deposit ultrathin polymer films onto different substrate materials. The film thickness and the chemical composition of the polymer are greatly influenced by the choice of the precursor, the deposition time, the electric power, the pressure, and additional gases.
In order to study various deposits, plasma processes were performed in a trifluoromethane (CHF3) discharge, diluted by argon.
By the variation of the above parameters, the coating thickness varied between 0.5 and 10 nm as determined by spectroscopic ellipsometry. The surface tension was determined according to the Owens-Wendt-Rabel-method; for coatings above 2.9 nm thickness, the surface energy remained constant, independent from the polymer thickness or the discharge parameters, at values of 15 mN/m disperse and 0.2 mN/m polar surface tension. At lower thicknesses, differences between advancing contact angles (representing the low-energy parts) and receding contact angles (representing high energy surface contributions) were observed. In the examined coatings, this behavior is attributed to the partial inset of polymer growth for mild plasma conditions, and further correlated to data from AFM and XPS measurements.