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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Polymer Dynamics
CPP 33.6: Topical Talk
Donnerstag, 29. März 2012, 11:15–11:45, C 264
Shear inversion of polymer-brush bilayers with embedded colloids — •Torsten Kreer1 and Andre Galuschko2 — 1Leibniz-Institut fuer Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden — 2Institut fuer Theoretische Physik, Georg-August Universitaet, 37077 Goettingen
Based on a recent scaling approach to describe the shear motion of polymer-brush bilayers at constant velocity, the response of bilayers with colloidal inclusions to highly non-stationary inversion processes is discussed by means of molecular dynamics simulations and scaling theory. Bilayers with a simple (dimeric) solvent reveal an overshoot for the shear stress, while simulations of dry brushes without explicit solvent molecules fail to display this effect. For the first time, it is demonstrated that mechanical instabilities can be controlled by the inclusion of macromolecular structures, such as colloids of varying softness. A characteristic time for conformational and collective responses under highly non-stationary shear is introduced. It can be expressed in terms of the equilibrium properties of the bilayer.