Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 34: Crystallization, Nucleation, Self Assembly I (joint session CPP/DY, organized by CPP)
CPP 34.9: Vortrag
Mittwoch, 9. März 2016, 12:00–12:15, H42
Interface & confinement induced order and orientation in thin films of Poly-Caprolactone — •Wilhelm Kossack1, Anne Seidlitz2, Thomas Thurn-Albrecht2, and Friedrich Kremer1 — 1Universität Leipzig, Institute for exp. physics 1,04103 Leipzig — 2Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, 06120 Halle/Saale
Infrared-transition moment orientational analysis (IR-TMOA), X-ray Diffraction (XRD) measurements and model calculations are combined to study interface and confinement induced order and orientation in thin (h≈11 × 10−6 m) films of Poly-caprolactone (PCL) prepared by drop-casting on silicon wafers. Depending on the crystallization temperature, 303 K ≤ Tx≤ 333 K, spherulites with a diameter of 1× 10−6 m ≤ d S ≤ 500× 10−6 m form. Macroscopic order of the crystalline lamellae is imposed by spatial (d S>h) and interfacial interactions and quantified IR-TMOA and XRD pole figures. Both techniques rely on the relative orientation of sample and incident radiation, and measure, in case of PCL, the orientation distribution of complementary crystal directions. This allows to (1) correlate the directions of the transition moments with the crystal axes; and (2) estimate the volume fractions of flat- or edge on lamellae as induced by the different interfaces, as well as the fractions of surface-induced- or bulk-nucleated spherulites in dependence on Tx. The contribution of substrate induced spherulitic structures rises with Tx=323 K up to ∼ 12 vol%, whereas no indications of edge on lamellae at the free surface are found. The bulk phase, on the other hand, dominates at Tx≤313 K.