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SKM-SYMF: SKM-Symposium Heterogenous Nucleation and Microstructure Formation: Steps towards a System- and Scale-bridging Understanding

SKM-SYMF 1: Heterogenous Nucleation and Microstructure Formation: Steps towards a System- and Scale-bridging Understanding

SKM-SYMF 1.4: Hauptvortrag

Donnerstag, 17. März 2011, 16:00–16:30, TRE Ma

Polymer Crystallization: Ordered Structures in Complex Systems — •Jens-Uwe Sommer — Leibniz-Institut für Polymerforschung Dresden, Hohe Straße 6, 01069 Dresden — Insitut für Theoretische Physik, Technische Universität Dresden, Zellescher Weg 17, 01069 Dresden

The crystallization of long chain molecules requires two ordering processes which take place simultaneously: Transition of each chain from the randomly coiled state into the partially folded and extended state, and the growth of a regular crystalline structure which involves the attachment of many chains. This leads to complex crystallization and nucleation pathways which usually result in non-equilibrium meta-stable states. I will first discuss some issues of possible equilibrium states of chain crystals [1]. Then, coarse grained models which describe the growth and melting behavior of polymer crystals in thin films are presented [2]. Here, I indicate the essential role of the internal transition of chain conformations for the growth of polymer crystals. Finally, large scale molecular dynamics simulations are presented which allow to investigate molecular details of single lamellar growth out of an entangled polymer melt [3]. Spatial-temporal measures of the state of order are introduced to detect precursor states of crystallizing chains during the crystallization pathway.

[1] J.-U. Sommer, Eur. Phys. J. E 19, 413 (2006)

[2] J.-U. Sommer and G. Reiter, J. Chem. Phys. 112, 4384 (2000)

[3] C.-F. Luo and J.-U. Sommer, Phys. Rev. Lett. 102, 147801 (2009)