Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: Polymer Physics II
CPP 21.5: Vortrag
Mittwoch, 25. März 2009, 10:30–10:45, ZEU 114
Polymer melt dynamics studied by Nuclear Magnetic Resonance — Patrick Hübsch1, •Fabian Vaca Chavez1, Wolfgang Binder2, Ronald Zirbs2, and Kay Saalwächter1 — 1Institute of Physics - Faculty of Natural Sciences II, Martin-Luther-University Halle-Wittenberg, Betty-Heimann-Str. 7, 06120, Haale, Germany — 2Macromolecular Chemistry Group, Institute of Chemistry, Heinrich Damerow Strasse 4, 06120, Halle, Germany
Proton Multiple-Quantum (MQ) NMR is a powerful technique to investigate polymer dynamics due to its sensitivity to molecular motions on very different timescales [1]. In this work, we apply MQ NMR to linear poly(cis-1,4-isoprene) and poly(isobutylene) of different molecular weight above the glass transition over suitable ranges of temperature, in order to establish the dynamic regimes predicted by the tube model, and, for the first time, to extract actual time scale information. This directly complements many neutron scattering studies, which are restricted to the sub-µs-timescale. Measurements on PIB-grafted silica particles with different molecular weights and different chain densities on the surface of the particle are also shown. The data is analyzed by establishing scaling laws which can be directly associated with different dynamic regimes predicted by the tube/reptation model [2]. Full analytical analyses based on a correlation function which explicitly includes segmental, Rouse, and reptation dynamics are discussed.
[1] K. Saalwächter, Prog. NMR Spect., 2007, 51, 1-35. [2] R. Graf, A. Heuer, H.W. Spiess, Phys. Rev. Lett., 1998, 80, 5738-5741.