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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: Crystallization, Nucleation and Self Assembly II
CPP 9.8: Talk
Monday, March 31, 2014, 17:15–17:30, ZEU 260
Pattern Formation in Polymer Single Crystals — Hui Zhang1, Bin Zhang1, Maximilian Vielhauer2, Rolf Mülhaupt2,3, Moritz Baier4, Stefan Mecking4, and •Günter Reiter1,3 — 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.