Author:

Abstract:

We want to study both experimentally and theoretically, micro- versus macro-rheological effects in the structural evolution of particle suspensions as affected by the motion of spherical inclusions. Gravity field exerts a pressure on the inclusions which may induce motion, depending on the local rheological properties, and modification of the dynamic behavior of the suspension. The effect of the inclusions on the microstructural evolution of the suspension during macroscopic flow and after flow cessation will be studied, whereby structure may evolve or not until yield stress recovery. The study will include the influence of the macroscopic rheological behavior of the suspension, while particle shape (from spheres to rods or platelets) and interparticle potential will be varied. For the experimental study, we will use model systems consisting of suspensions of particles of well-defined size, shape and interaction potential, as well as systems which are relevant for applications in the food industry (e.g. suspensions of protein or fat particles). Rheology and rheo-optical techniques will be used, in particular following developments in FZ Juelich and other experts in the field involved in the DiStruc project. Experimental results will be compared to theoretical predictions whenever possible, also in interaction with other groups.