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SYSE: Simulation and experiment

SYSE 1: Simulation and experiment - spanning the bridge between microscopic and macroscopic scales

SYSE 1.3: Hauptvortrag

Dienstag, 25. März 2003, 12:00–12:30, ZEU/160

From the melt via mesomorphic and granular-crystalline layers to lamellar crystallites: The major route in polymer crystallization — •Gert Strobl — Physikalisches Institut, Universitaet Freiburg, 79104 Freiburg

Based on broad and detailed evidence from a large variety of experiments on several polymer systems carried out by other authors and our-selves a novel concept for understanding the crystallization of polymers from the melt is developed. The experiments generally indicate that the formation and growth of the lamellar crystallites is a multi-step process passing over intermediate states. We suggest a specific route which is compatible with the observations. It is proposed that the initial step is always the creation of a mesomorphic layer which spontaneously thickens,up to a critical value, where it solidifies through a cooperative structural transition. The transition produces a granular crystalline layer, which transforms in the last step into homogeneous lamellar crystallites. Lit.: G.Strobl, Eur.Phys.J.-E,3,165 (2000) M.Al-Hussein, G.Strobl, Eur.Phys.J.-E,6,305(2001) M.Grasruck, G.Strobl, Macromolecules, in press (2002)