Regensburg 2004 – wissenschaftliches Programm
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DS: Dünne Schichten
DS 13: Schichteigenschaften III
DS 13.2: Vortrag
Mittwoch, 10. März 2004, 17:00–17:15, HS 31
Mechanical properties of laser deposited PMMA films — •Erik Süske1, Thorsten Scharf1, Peter Schaaf2, Elena Panchenko3, Dorit Nelke3, Michael Buback3, Harald Kijewski4, and Hans-Ulrich Krebs1 — 1Institut für Materialphysik, Tammannstr. 1, 37077 Göttingen — 2II. Phys. Institut, Tammannstr. 1, 37077 Göttingen — 3Institut für physikalische Chemie, Tammannstr. 6, 37077 Göttingen — 4Institut für Rechtsmedizin, Windausweg 2, 37073 Göttingen
Poly-(methyl methacrylate) (PMMA) films were laser deposited at a wavelength of 248 nm in UHV at substrate temperatures up to 250 ∘C and characterized by infrared spectroscopy (FTIR), size eclusion chromatography (SEC), thermogravimetric analysis (TGA) and microhardness measurements. The FTIR spectra indicate a chemical structure closed to the bulk material, probably caused by a radical polymerization mechanism, with a small amount of cross-linked polymer. Nevertheless, after deposition the chain length of the PMMA is reduced to about 6000 g/mol. Due to this changes, the mechanical properties of the films vary dramatically from the bulk polymer, e.g. the hardness increases by a factor of five. During annealing the mechanical properties of the films can be systematically varied to values closed to that of bulk samples. The deposition process and properties of the films are discussed with respect to changes in chemical structure, number of cross links and chain length, while the changes in mechanical properties are concerned with relaxation effects and the stability of the polymer.