Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 29: POSTER: Polymer physics
CPP 29.66: Poster
Dienstag, 8. März 2005, 16:30–18:30, Poster TU D
Determination of the Overlap Concentration of Polymers in a Good Solvent using Fluorescence Correlation Spectroscopy (FCS) — •Ute Lippert1, Heiko Zettl1, Alexander Böker1, Holger Schmalz2, Axel H. E. Müller2, and Georg Krausch1 — 1Physikalische Chemie II, Universität Bayreuth — 2Makromolekulare Chemie II, Universität Bayreuth
For polymer solutions the dilute and concentrated regime is well investigated by light scattering, rheology and fluorescence recovery after photo bleaching. The crossover concentration between the dilute and semi-dilute regime and the properties of solutions in the semi-dilute regime are less investigated. This concentration range is difficult to assess with the above mentioned methods. Here, we use fluorescence correlation spectroscopy to determine the diffusion behavior of single polymer chains in solution. We are able to assign the crossover between dilute and semi-dilute for molecular weights in the range of 4 kg/mol to 1500 kg/mol. We find a scaling law for the dependence of the overlap concentration on molecular weight in agreement with theoretical predictions.