Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Focus: Rheology I (joint focus with DRG)
CPP 35.8: Vortrag
Donnerstag, 29. März 2012, 17:15–17:30, C 243
Transient rheology of concentrated suspensions — •Miriam Siebenbürger1, Thomas Voigtmann2,3,4, Christian Amann2, Matthias Fuchs2, and Matthias Ballauff1 — 1Institut für Weiche Materie und Funktionale Materialien, Helmholtz Zentrum Berlin für Materialien und Energie, Berlin, Deutschland — 2Fachbereich Physik, Universität Konstanz, Konstanz, Deutschland — 3Zukunftskolleg, Universität Konstanz, Konstanz, Germany — 4Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Köln, Deutschland
Suspensions of sherical thermosensitive core-shell colloids are excellent model system for the study of the fluid to glass transition. In the last years the phase behavior, the linear [1] and nonlinear [2] viscoelastic properties as well as the rheological properties in stationary flow could be described in detail with the Mode Coupling Theory (MCT). Here we report on the transient rheology of these suspensions: i) For the start-up of shear aging-dependent overshoot phenomena are observed experimentally. The overshoot was also found by simulations [3] and can be described by a new schematic MCT-model. ii) The stress relaxation after switching off steady shear was found to be sensitive for the onset of the glassy state. iii) Finally, we present a systematic investigation of the creep behavior of the suspension in the glassy state.
References:
[1] M. Siebenbürger et al., J. Rheol. 53, 707 (2009).
[2] J. M. Brader et al., Phys. Rev. E 82, 061401 (2010).
[3] J. Zausch et al., J. Phys. Condens. Mat. 20, 404210 (2008).