Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 23: Polymer Dynamics
CPP 23.5: Vortrag
Mittwoch, 13. März 2013, 10:45–11:00, H39
Studies of entangled polymer dynamics by NMR: validity of tube model variants and nanoparticle effects — •Filipe Furtado1, Joshua Damron1, Marie-Luise Trutschel1, Mansi Agarwal2, Charles Zukoski2, and Kay Saalwächter1 — 1Institut f. Physik-NMR, Martin-Luther-Univ. Halle, Deutschland — 2University of Illinois at Urbana-Champaign, USA
The validity of fixed-tube model remains a matter of intense debate. Ongoing discussions include the dynamics of the tube itself and of contour-length fluctuations (CLF) and constrained release (CR) effects. Suitable NMR experiments [1] were used to investigate CR effects by probing the dynamics of diluted protonated polybutadiene (PB) chains in matrices of deuterated (NMR-invisible) high molecular weight PB chains. Such dilution experiments have been reported to be subject to a bias due to interchain correlations in NMR T1 relaxation experiments [2], but these effects have been shown to not significantly affect our experiments. CLF was investigated on deuterated pseudotriblock copolymers (2H-1H-2H). Furthermore, we hereby present the first NMR experiments clearly confirming the recently predicted nanoparticle effect on chain disentanglement [3] on a molecular scale by monitoring the influence of polyhedral oligomeric silsesquioxanes (POSS) on the disentanglement time of polyethyleneoxide melts.
[1] F. V. Chávez et al., Phys. Rev. Lett., 2010, 104, 198305
[2] A. Herrmann et al., Macromolecules, 2012, 45, 6516
[3] Y. Li et al., Phys. Rev. Lett., 2012, 20121, 09, 118001