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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.68: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Chain Ordering and Diffusion in Polymer Networks: New Insights by Low-Field Proton NMR and FCS — •Kay Saalwächter, Felix Kleinschmidt, and Giorgio Modesti — Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany

We have recently developed a new approach to ¹H multiple-quantum NMR, which yields qualitatively new information on chain ordering, dynamics, and heterogeneities in polymer networks. The technique can be implemented on simple low-field NMR spectrometers without compromise in data quality [1], and has been applied to investigations of filler effects in technical elastomers and the swelling process of model networks. In the latter case, substantial chain-order heterogeneities have been found to develop on swelling, thus challenging established models [2]. Here, our most recent results on details of the chain dynamics in natural rubber are reported, where we have also found substantial deviations from accepted model predictions. We further study the influence of swelling heterogeneities on diffusive transport in model networks by fluorescence correlation spectroscopy (FCS) and pulsed field-gradient NMR.

[1] K. Saalwächter, J. Am. Chem. Soc. 125 (2003) 14684.

[2] K. Saalwächter et al., Macromolecules 37 (2004) 8556.