Berlin 2015 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Interfaces and Thin Films II (joint session with CPP)
DS 18.3: Vortrag
Dienstag, 17. März 2015, 14:45–15:00, C 243
Instabilities in PS-PVP polymer blends thin films driven by surface tension and temperature effects — •Marlena Filimon1, Jean-Nicolas Audinot2, Patrick Grysan2, Jörg Baller1, and Roland Sanctuary1 — 1Laboratory for the Physics of Advanced Materials, University of Luxembourg, Luxembourg — 2Department of Science and Analysis of Materials , Centre de Recherche Public-Gabriel Lippmann, Belvaux, Luxembourg
In thin supported films of polymer blends, in addition to composition and molecular weight of components, the structure is dependent on the surface energies of the components and on geometrical constraints induced by confinement in a thin film. Two-dimensional patterns attributed to the Marangoni instability and dependence of the Gibbs free energy of mixing components were observed for a interesting polymer blend ( polystyrene/poly(vinylpyrollidone) (PS-PVP)) thin films. As tools for investigating the nano-size domains structures of thin polymer blends (~150 nm) , we exploited Tapping-Mode Atomic Force Microscopy (TM-AFM) and Nano-dynamic Secondary Ion Mass Spectrometry technique (Nano-SIMS 50. Additionally, wetting properties of the substrate and influences of these instabilities are studied using wetting measurements - contact angle. We propose a possible formation mechanism for presented patterns and show that the mechanism is relevant to the Marangoni instability. The relevant variables which can affect the morphological evolution such as surface enrichment and temperature dependence were also discussed.