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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 5: Polymer Physics II
CPP 5.5: Vortrag
Montag, 26. März 2007, 15:30–15:45, H40
The scattering of polymer gels and networks: Origin and relation to network structure — •Michael Lang1 and Jens-Uwe Sommer2 — 1University of North Carolina, Department of Chemistry, Venable Hall, 27599 Chapel Hill, N.C., United States of Amerika — 2Leibniz Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden
We utilize computer simulations to directly relate connective and topological structure, density, and particle fluctuations with the scattering of polymer gels. We observe density fluctuations on three different length scales upon swelling independent of wheter the original sample was homogeneous or heterogeneous in the dry state. The observed density fluctuations and length scales are a) dynamic fluctuations on the length scale of single monomers or substrands of the polymer chains due to thermal fluctuations, b) static density fluctuations on the length scale comparable to the size of prime network rings which result from network connectivity, and c) static density fluctuations on length scales larger larger than the size of network rings due to frozen in density fluctuations of the elastically active material, whereby origin, length scale, and amplitude of these longest fluctuations depend mostly on the preparation conditions of the sample. Connective and topological analysis, scattering curves, dynamic as well as static spatial density profiles, and the pair correlations of cross-links and polymers are compared and discussed with the results obtained from polymer solutions at the same concentrations.