Time-Dependent Flow in Arrested States (A06)

• Subject Area: Experimental Condensed Matter Physics
• Term: from 2005 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5485412

This project concerns the combined theoretical and experimental investigation of highly concentrated colloidal liquids and dynamically arrested states under time-dependent shear. In the second funding period (our first funding period) a new and comprehensive theoretical framework was developed to describe concentrated liquids as well as colloidal glasses and gels subject to an arbitrary flow history. Furthermore, a shear cell was designed, constructed and tested which allows us to study colloidal suspensions under flow with the confocal microscope and light scattering. This theoretical approach and experimental set-up was already applied to concentrated colloidal suspensions and yielded consistent results. We now want to exploit this new methodology and apparatus to investigate in detail the time-dependent response of dense fluids and arrested states, bridging the gap between the microscopic and macroscopic levels of description. Particular emphasis will be given to, (i) switch-on shear flow, (ii) switch-off shear flow, (iii) large amplitude oscillatory shearing. The competition of timescales and dependence on flow history is expected to lead to novel features in both the rheological response and microscopic dynamics.

• DFG Programme: CRC/Transregios
• Subproject of: TRR 6: Physics of Colloidal Dispersions in External Fields
• Applicant Institution: Heinrich-Heine-Universität Düsseldorf
• Co-Applicant Institution: Universität Konstanz
• Project Heads: Professor Joseph M. Brader, Ph.D., until 6/2010; Professor Dr. Stefan U. Egelhaaf (†); Professor Dr. Matthias Fuchs