Viscoelasticity and shear flow of concentrated, non-crystallizing colloidal suspensions: Comparison with Mode-Coupling Theory

Abstract

We present a comprehensive rheological study of a suspension of thermosensitive particles dispersed in water. The volume fraction of these particles can be adjusted by the temperature of the system in a continuous fashion. Due to the finite polydispersity of the particles (standard deviation: 17%), crystallization is suppressed and no fluid-crystal transition intervenes. Hence, the moduli $G^{\prime }$ and $G"$ in the linear viscoelastic regime as well as the flow curves (shear stress $\sigma (\dot{\gamma })$ as the function of the shear rate $\dot{\gamma }$) could be measured in the fluid region up to the vicinity of the glass transition. Moreover, flow curves could be obtained over a range of shear rates of 8 orders of magnitude while $G^{\prime }$ and $G"$ could be measured spanning over 9 orders of magnitude. Special emphasis has been laid on precise measurements down to the smallest shear rates/frequencies. It is demonstrated that mode-coupling theory generalized in the integration through transients framework provides a full description of the flow curves as well as the viscoelastic behavior of concentrated suspensions with a single set of well-defined parameters.

References in corpus (2)

• Recent experimental probes of shear banding
• A mode coupling theory for Brownian particles in homogeneous steady shear flow

Cited by in corpus (1)

• Glass Rheology: From mode-coupling theory to a dynamical yield criterion