Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Polymer Crystallization and Semicrystalline Polymers
CPP 40.1: Topical Talk
Donnerstag, 17. März 2011, 10:30–11:00, ZEU 160
Crystallization in block copolymer thin films — •Christine M. Papadakis1, Charles Darko1, and Günter Reiter2 — 1TU München, Physikdepartment, Physik weicher Materie, Garching — 2Universität Freiburg, Fakultät für Physik
Polymer crystallization in microphase-separated block copolymers proceeds in thermodynamic confinement. To characterize the crystalline structure, e.g. the crystal orientation, macroscopic alignment of the domains is required. Numerous experiments have been carried out on bulk samples which were macroscopically oriented by high amplitude shear. The thin film geometry has the advantage that the domains orient macroscopically, and imaging methods can be used to characterize the surface texture of crystallized films. Grazing-incidence X-ray diffraction and small-angle scattering allow a detailed characterization of the crystalline structure in a wide range of length scales.
Two examples will be presented. In thin films of lamellae-forming poly(styrene-b-(ethylene oxide)), we have found that the resulting crystalline structure – the orientation of the chain stems, their orientational distribution and the size of the crystallites – strongly depends on the degree of supercooling. In thin films of cylinder-forming poly(isoprene-b-(ethylene oxide)), crystallization can only proceed very slowly and only at the film surface which is due to a mismatch in crystalline layer thickness and cylinder radius.