Berlin 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Polymerphysics II
CPP 30.9: Vortrag
Donnerstag, 28. Februar 2008, 16:15–16:30, C 130
Calculation of the segmental order parameter for a polymer chain in good solvent — •Zoryana Usatenko1,2 and Jens-Uwe Sommer1 — 1Leibniz Institute for Polymer Research Dresden e.V.,01069 Dresden,Germany — 2Institute for Condensed Matter Physics, NAS Ukraine,79011 Lviv,Ukraine
We have calculated the segmental tensor order parameter of flexible polymer chains in weak good solvent. This quantity is directly observable in multi-quantum NMR experiments. We have used the Edwards model for polymer chains and have applied direct perturbation expansion with respect to excluded volume interactions in one loop order. The obtained results indicate that the distribution of the tensor order parameter is not homogeneous along the chain as expected for ideal Gaussian statistics. Overall segmental order is lower as compared to Gaussian chains and decays towards the chain ends [1]. These results are in agreement with computer simulation studies on single chains with fixed ends in good solvent. The overall reduction of the tensor order parameter has been also observed in NMR experiments on swollen polymer networks [2].
[1] Z.Usatenko, J.-U.Sommer, Macromolecular theory and simulations, 2007 (in press).
[2] K. Saalwächter and J.-U. Sommer, Macromol.Rapid Commun.28, 1455 (2007).