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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 1: DRG-DPG SYMPOSIUM Rheology I
CPP 1.3: Vortrag
Montag, 25. Februar 2008, 10:15–10:30, C 130
Optical Microrheology applied to different Soft Matter Systems and compared to Classical Bulk Rheology — Anna Kozina1, •Pedro Diaz-Leyva1,2, Christian Friedrich2,3, and Eckhard Bartsch1,2 — 1Institut für Makromolekulare Chemie, Universität Freiburg, Germany — 2Institut für Physikalische Chemie, Universität Freiburg, Germany — 3Freiburger Materialforschungszentrum, Universität Freiburg, Germany
Over years it has been very important to understand how the macroscopic properties of soft materials are depending on their micro-structure. Concerning mechanical properties such as viscosity and/or elasticity, they have been measured typically by Classical Bulk Rheology (CBR) which works at a macroscopic level. In this work we discuss a technique known as Optical Microrheology (OMR) which characterize the same mechanical properties, but using a microscopic approach. This method exhibits two important features: First, OMR is a non-invasive and non-destructive technique. Second, OMR is capable to reach high frequencies. We explore the capabilities of OMR studying several systems showing a clear viscoelastic behavior, but appreciably different in terms of microstructure. We use Dynamic Light Scattering in order to measure the dynamics exhibited in the materials, and consequently we can get the rheological moduli G′(ω) and G″(ω). We compare our results with those obtained by CBR applied on the same systems. Finally we discuss the possible origin of discrepancies between the results obtained with OMR and CBR respectively.