Europhys. Lett.
Volume 75, Number 6, September 2006
Page(s) 915 - 921
Section Condensed matter: structural, mechanical and thermal properties
Published online 09 August 2006
Europhys. Lett., 75 (6), pp. 915-921 (2006)
DOI: 10.1209/epl/i2006-10203-9

Nonlinear viscoelasticity of metastable complex fluids

K. Miyazaki1, H. M. Wyss2, D. A. Weitz2 and D. R. Reichman1

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 in final form 21 July 2006
published online 9 August 2006

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.

64.70.Pf - Glass transitions.
83.60.Rs - Shear rate-dependent structure (shear thinning and shear thickening).
83.80.Hj - Suspensions, dispersions, pastes, slurries, colloids.

© EDP Sciences 2006