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Far-from-equilibrium sheared colloidal liquids: Disentangling relaxation, advection, and shear-induced diffusion

Cornell Affiliated Author(s)

Author

N.Y.C. Lin
S. Goyal
X. Cheng
R.N. Zia
F.A. Escobedo
Itai Cohen

Abstract

Using high-speed confocal microscopy, we measure the particle positions in a colloidal suspension under large-amplitude oscillatory shear. Using the particle positions, we quantify the in situ anisotropy of the pair-correlation function, a measure of the Brownian stress. From these data we find two distinct types of responses as the system crosses over from equilibrium to far-from-equilibrium states. The first is a nonlinear amplitude saturation that arises from shear-induced advection, while the second is a linear frequency saturation due to competition between suspension relaxation and shear rate. In spite of their different underlying mechanisms, we show that all the data can be scaled onto a master curve that spans the equilibrium and far-from-equilibrium regimes, linking small-amplitude oscillatory to continuous shear. This observation illustrates a colloidal analog of the Cox-Merz rule and its microscopic underpinning. Brownian dynamics simulations show that interparticle interactions are sufficient for generating both experimentally observed saturations. © 2013 American Physical Society.

Date Published

Journal

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics

Volume

88

Issue

6

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891790974&doi=10.1103%2fPhysRevE.88.062309&partnerID=40&md5=7a902aadeac2574c3f498951f5ab7f07

DOI

10.1103/PhysRevE.88.062309

Group (Lab)

Itai Cohen Group

Funding Source

1232666

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