Memory effects in dense colloidal suspensions

Understanding the rheological behaviour of dense colloidal suspensions is of huge interest for industrial and technological applications. As they are amorphous yield stress materials, the mechanical response, and in particular the reversibility, depends strongly on the external applied deformation.
We propose to investigate the microscopic origin of the macroscopic flow of a dense colloidal suspension at room temperature by considering Brownian dynamic simulations of a binary quasi hard spheres mixture. By performing cyclic shear deformation, we investigate the shear-history effects that occur for the different amount of pre-strain considered. A particular interest is devoted to the characterisation of the Bauschinger effect. To probe the origin of this phenomenon we explore microscopic structural and dynamical observables that aim to inform on the degree of reversibility in the suspension. An interpretation of our results with the generalized Maxwell model derived within the framework of MCT-ITT will be discussed.