Yield Stress Materials in Soft Condensed Matter (original) (raw)

We present a comprehensive review of the physical behavior of yield stress materials in soft condensed matter, which encompasses a broad range of soft materials from colloidal assemblies and gels to emulsions and non-Brownian suspensions. All these disordered materials display a nonlinear response to an external mechanical forcing, which results from the existence of a finite force threshold for flow to occur, the yield stress. We discuss both the physical origin and the rheological consequences associated with this nonlinear behavior. We give an overview of the different experimental techniques developed to measure the yield stress. We discuss extensively the recent progress concerning a microscopic description of the flow dynamics of yield stress materials, emphasizing in particular the role played by relaxation timescales, the interplay between shear flow and aging behavior, the existence of inhomogeneous shear flows and shear bands, wall slip, and non-local effects in confined geometries. We finally review the status of modeling of the shear rheology of yield stress materials in the framework of continuum mechanics.