Nonlinear viscoelasticity of metastable complex fluids

Abstract

Many metastable complex fluids such as colloidal glasses and gels show\ndistinct nonlinear viscoelasticity with increasing oscillatory-strain\namplitude; the storage modulus decreases monotonically as the strain amplitude\nincreases whereas the loss modulus has a distinct peak before it decreases at\nlarger strains. We present a qualitative argument to explain this ubiquitous\nbehavior and use mode coupling theory (MCT) to confirm it. We compare\ntheoretical predictions to the measured nonlinear viscoelasticity in a dense\nhard sphere colloidal suspensions; reasonable agreement is obtained. The\nargument given here can be used to obtain new information about linear\nviscoelasticity of metastable complex fluids from nonlinear strain\nmeasurements.\n