Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Crystallization, Nucleation and Self Assembly II

CPP 9.8: Vortrag

Montag, 31. März 2014, 17:15–17:30, ZEU 260

Pattern Formation in Polymer Single Crystals — Hui Zhang¹, Bin Zhang¹, Maximilian Vielhauer², Rolf Mülhaupt^2,3, Moritz Baier⁴, Stefan Mecking⁴, and •Günter Reiter^1,3 — ¹Institute of Physics, University of Freiburg, 79104 Freiburg, Germany — ²Institut für Makromolekulare Chemie, University of Freiburg, 79104 Freiburg, Germany — ³Freiburger Materialforschungszentrum, University of Freiburg, 79104 Freiburg, Germany — ⁴Department of Chemistry, University of Konstanz, 78464 Konstanz, Germany

Polymer crystals typically grow at conditions far from thermodynamic equilibrium, resulting in chain-folded lamellar crystals. Even in single crystals, characterized by dendritic or faceted structures with a well-defined envelope reflecting the underlying crystal unit cell, polymers are folded and thus in a meta-stable state. Systematic investigations on such crystals led to a general concept of a nucleation of secondary lamellar crystals induced by an insertion mechanism on the amorphous fold surfaces. These secondary lamellar crystals are in registry with the underlying single crystal. The dependence of the number density of secondary lamellae on the width of the side branches of the underlying crystal suggests that nucleation was controlled by the morphology of the underlying crystal which, in turn, could be tuned by crystallization temperature and film thickness. Moreover, annealing such meta-stable single crystals allowed to unveil the initial morphological framework of a dendritic single crystal, i.e. the initial stages of growth.