Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster Session 2
CPP 37.3: Poster
Mittwoch, 2. April 2014, 15:00–19:00, P3
Molecular dynamics of poly(cis-1,4-isoprene) in 1- and 2-D confinement — •Emmanuel Urandu Mapesa1, Martin Treß1, Wycliffe Kiprop Kipnusu1, Manfred Reiche2, and Friedrich Kremer1 — 1Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany — 2Max-Planck Institute for Microstructure Physics, Weinberg, Halle (Saale), Germany
Broadband Dielectric Spectroscopy - in combination with a nanostructured electrode arrangement - is employed to study thin layers of poly(cis-1,4-isoprene) (PI). PI is further probed in the 2-D confining space of Anodic Aluminium Oxide (AAO) nanopores. We report that while the structural relaxation shows dependence on neither layer thickness nor molecular weight, the normal mode is dramatically influenced by confinement: (i) its relaxation strength is layer-thickness-dependent; (ii) for PI having a molecular weight Mw comparable to M* (i.e. the critical molecular weight below which Rouse dynamics dominate), the mean spectral position does not shift with layer thickness, (iii) in contrast, when Mw > M*, the relaxation strength and rate of the normal mode respond to the confinement; (iv) it is demonstrated, for the first time, that the polymer solution from which the thin layers are spincast has an impact on the chain dynamics; and (v) the extent by which the normal mode is affected depends on the dimensionality of confinement. Put together, these results show that while the chain dynamics are altered in a manifold of ways (due, for instance, to interactions with the confining surface), the dynamic glass transition retains most of its bulk-like nature.