Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: Crystallization, Nucleation and Self Assembly I
CPP 14.3: Vortrag
Dienstag, 12. März 2013, 10:00–10:15, H39
Entanglement Related Memory Effect in Primary Nucleation of Polymers — •Chuanfu Luo1 and Jens-Uwe Sommer1,2 — 1Leibniz-Institut für Polymerforschung Dresden, Germany — 2Technische Universität Dresden, Germany
Polymer crystallization is a non-equilibrium process and highly dependent on the thermal history. In self-seeding experiments a polymer melt is prepared by melting semi-crystalline polymer for a short time, followed by a subsequent cooling process, which can result in strong position and orientation- correlations of the resulting crystals with the previously crystalline regions [1-2]. The origin of such a memory effect is still unclear. We found indications that this memory effect is related to the state of entanglement in the melt which is still incompletely re-entangled during the heating period. By using MD simulations combined with primitive path analysis (PPA)[3], we reproduced self-seeding effects in simulations and we can show that crystallization and in particular self-seeding is directly correlated with the entanglement state of the melt. Also, we show that self-seeding takes place even for the case that all individual chains are in the molten state before cooling. [1]A. Mamun et al., Macromolecules 40, 6296-6303 (2007) [2]J.-J. Xu et al., Nature Mater. 8, 348 (2009) [3]R. Everaers et al., Science 303, 823-826 (2004)