Berlin 2008 – scientific programme
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DS: Fachverband Dünne Schichten
DS 35: Nanostructured block copolymer films (SYSA 8)
DS 35.4: Talk
Thursday, February 28, 2008, 18:00–18:15, H 2032
Thin films of diblock copolymers having one crystalline block — •Charles Darko1, Ioan Botiz2, Günter Reiter2, Dag W. Breiby3, Jens W. Andreasen4, Detlef-M. Smilgies5, Stephan V. Roth6, and Christine M. Papadakis1 — 1Physikdepartment E13, TU München — 2ICSI, CNRS, Mulhouse, France — 3Norwegian University of Science and Technology, Trondheim, Norway — 4Risø National Laboratory, Denmark — 5Cornell University, Ithaca, USA — 6HASYLAB at DESY, Hamburg
In thin films of symmetric poly(styrene-b-ethyleneoxide) (PS-b-PEO) diblock copolymers, the surface morphologies obtained are strongly influenced by the internal structural rearrangement within the films which are associated with different mechanisms of crystal growth of PEO. With grazing incidence small and wide angle X-ray scattering, we obtained information about the mesoscopic structures as well as the crystallite orientations within the thin films. We observed lamellae parallel to the substrate in all films, but the internal structure and the degree of preferred orientation depends strongly on crystallization temperature: When crystallized at 25∘C, the c-axis is oriented at approximately 35∘ with respect to the film normal with a broad distribution. At a crystallization temperature of 50∘C, the c-axis becomes perfectly perpendicular to the substrate/film interface. The lamellar repeat distances increase with crystallization temperature. The information on the inner structures is compared to the surface textures measured by optical and atomic-force microscopy (AFM).