Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 49: P14: Polymer Dynamics

CPP 49.5: Poster

Mittwoch, 18. März 2015, 10:00–13:00, Poster A

Diffusion of crystalline lamella in a semicrystalline polymer — •Martin Neumann, Stefan Krause, Christian von Borczyskowski, and Robert Magerle — Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Chemnitz, Germany

During crystallization, elastomeric polypropylene (ePP) with 15 % crystallinity forms isolated ∼ 50-nm small crystalline lamella within the amorphous matrix and larger but immobile complexes of crystalline lamella. With Atomic Force Microscopy (AFM) we measured the diffusion of these small lamella in 60 nm thin polymer films at different temperatures and analyzed the diffusion trajectories to extract the diffusion coefficients. The temperature dependence of the data is well described by the Stokes-Einstein-Equation (SEE) and the Williams-Landel-Ferry-Equation (WLF). The size variation of the diffusing crystals led to a broad distribution of diffusion coefficients, which cannot completely be explained by the Stokes-Einstein-Equation (SEE). We identified heterogeneities of the crystal diffusion depending on the distance d_C between isolated crystals and the larger crystalline lamella. Isolated crystals moved up to 5 times slower when d_C was smaller than 50 nm. Our interpretation of this result is that there is an amorphous interphase layer around all crystalline lamella, which has an increased viscosity. This could be due to partly crystallized polymer coils, which are not able to diffuse like the completely amorphous ones.