Time-resolved structural organization and dynamics of colloidal gels submitted to combined shear flow and ultrasound waves: break-down/build

Controlling the time-dependent mechanisms of fluidization or softening of colloidal gels by external forces like shear flow or ultrasound (US) waves, is a major challenge in many industrial applications (coating, cement placement, tires, chemical, bio and agro industries). The evolution of the rheological properties of colloidal dispersions from gel-like to fluid-like behavior and the reversibility of the sol-gel transition, constitute in many cases the aim of the process or has a huge impact on the final product properties. In this work we aim at studying the effects of combined shear flow and US on colloidal gels. First, we will study the time-dependent evolution of the structural organizations of attractive aggregated colloids forming typically heterogeneous fractal open structures. Second, on repulsive colloids forming homogeneous space-filling structures, we will focus more precisely on the change in dynamics at micrometer length scales induced by acoustic waves propagation.