Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Focus: Polymer Crystallization - from Model Systems to New Materials II
CPP 40.6: Vortrag
Mittwoch, 22. März 2017, 17:00–17:15, ZEU 222
Creating micrometer-high stacks of correlated lamellar crystals of precision polyethylene by self-induced nucleation — •Sumit Majumder1, Hanna Busch2, Purushottam Poudel1, Stefan Mecking2, and Günter Reiter1 — 1Experimental Polymer Physics, University of Freiburg — 2Chair of Chemistry, University of Konstanz
Crystallizable polymers often form stacks of correlated lamellar crystals. Formation of such stacks of lamellae requires a mechanism of self-induced nucleation at the fold surface (H. Zhang et. al. Phys. Rev. Lett. 112, 237801, (2014)). However, in polymer thin films, scarce availability of polymers on the fold surface and a low nucleation probability in general typically limit the formation of such stacks of lamellar crystals. Here, we investigate the possibility of enhancing stacking of lamellar crystals in thin films by introducing precisely spaced bulky methyl-phosphonate groups along the backbone of polyethylene. Presence of these bulky side groups impose constraints on folding and eliminate the possibility of lamellar thickening. We present experimental observations indicating that the stacking mechanism can be controlled by film thickness, crystallization temperature and molecular weight.