Nonlinear viscoelasticity of metastable complex fluids

¹ Department of Chemistry, Columbia University 3000 Broadway, New York, NY 10027, USA
² Department of Physics & DEAS, Harvard University - Cambridge, MA 02138, USA

Received: 15 February 2006
Accepted: 21 July 2006

Abstract

Many metastable complex fluids such as colloidal glasses and gels show distinct nonlinear viscoelasticity with increasing oscillatory-strain amplitude; the storage modulus decreases monotonically as the strain amplitude increases whereas the loss modulus has a distinct peak before it decreases at larger strains. We present a qualitative argument to explain this ubiquitous behavior and use mode-coupling theory (MCT) to confirm it. We compare theoretical predictions to the measured nonlinear viscoelasticity in a dense hard-sphere colloidal suspension; reasonable agreement is obtained. The argument given here can be used to obtain new information about linear viscoelasticity of metastable complex fluids from nonlinear strain measurements.