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SOE: Fachverband Physik sozio-ökonomischer Systeme
SOE 9: Poster - Glasses / Stat. Phys. Bio. / Networks (joint session DY/BP/CPP/SOE)
SOE 9.13: Poster
Tuesday, April 1, 2014, 09:30–12:30, P1
Molecular Order and Dynamics of Nanometric Thin Layers of Poly(styrene-b-1,4-isoprene) Diblock Copolymers — •Wycliffe K. Kipnusu1, Mahdy M. Elmahdy1, Martin Tress1, Emmanuel U. Mapesa1, Detlef-M. Smilgies2, Jianqi Zhang3, Christine M. Papadakis3, and Friedrich Kremer1 — 1Institute of Experimental physics I, Linnstr.5, 04103, Leipzig — 2CHESS, Wilson Laboratory, Cornell University, Ithaca, NY 14853, USA — 3Technische Universität München, Physik-Department, James-Franck-Straße 1, 85748 Garching, Germany
Order and dynamics of poly(styrene-block-1,4-isoprene), P(S-b-I) diblock copolymers in nanometer thin layers with different isoprene volume fraction (fPI) and identical molecular weight of the styrene blocks are studied by a combination of Grazing-Incidence Small-Angle X-ray Scattering (GISAXS), Atomic Force Microscopy (AFM) and Broadband Dielectric Spectroscopy (BDS). GISAXS and AFM reveal randomly oriented lamellar structures in the films and a parallel orientation at the top surface, respectively. Using BDS, three well separated relaxation processes are detected, (i) and (ii) the dynamic glass transitions (segmental mode) in the styrene and isoprene blocks respectively and (iii) the normal mode relaxation representing fluctuations of the isoprene chain as a whole or parts of it. While the two former do not show any thickness dependence in their spectral positions, the latter becomes faster with decreasing sample thickness. This reflects the difference in the length-scale on which the molecular fluctuations take place.