Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 36: Colloids and Complex Liquids II
CPP 36.7: Vortrag
Mittwoch, 2. April 2014, 16:45–17:00, ZEU 114
Shear banding in weakly attractive soft jammed materials — •Ehsan Irani1, Pinaki Chaudhuri2, and Claus Heussinger1 — 1Institut für Theoretische Physik, Georg-August-Universität Göttingen, Göttingen, Germany — 2Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
We study the rheology of a system of weakly attractive soft particles close to jamming. Lees-Edward boundary conditions are used to impose a shear flow in two dimensions. Shear stress as a function of shear rate shows non-monotonic behavior signaling a mechanical instability. This leads to persistent spatial heterogneities in flow, which becomes prominent with increasing system size. In the yield stress regime, a fragile solid is formed even far below the jamming point. A scaling argument is presented that connects the yield stress to the attraction strength and the connectivity of the fragile solid. The shear-banding instability is explained with the breakdown of the solid and an associated loss of structure. This mechanism could be a scenario to explain shear banding in different materials with short-range attractive forces.