High-bandwidth viscoelastic properties of aging colloidal glasses and gels.

Journal Article (Journal Article)

We report measurements of the frequency-dependent shear moduli of aging colloidal systems that evolve from a purely low-viscosity liquid to a predominantly elastic glass or gel. Using microrheology, we measure the local complex shear modulus G;{*}(omega) over a very wide range of frequencies (from 1Hzto100kHz ). The combined use of one- and two-particle microrheology allows us to differentiate between colloidal glasses and gels-the glass is homogenous, whereas the colloidal gel shows a considerable degree of heterogeneity on length scales larger than 0.5microm . Despite this characteristic difference, both systems exhibit similar rheological behaviors which evolve in time with aging, showing a crossover from a single-power-law frequency dependence of the viscoelastic modulus to a sum of two power laws. The crossover occurs at a time t_{0} , which defines a mechanical transition point. We found that the data acquired during the aging of different samples can be collapsed onto a single master curve by scaling the aging time with t_{0} . This raises questions about the prior interpretation of two power laws in terms of a superposition of an elastic network embedded in a viscoelastic background.

Full Text

Duke Authors

Cited Authors

  • Jabbari-Farouji, S; Atakhorrami, M; Mizuno, D; Eiser, E; Wegdam, GH; Mackintosh, FC; Bonn, D; Schmidt, CF

Published Date

  • December 11, 2008

Published In

Volume / Issue

  • 78 / 6 Pt 1

Start / End Page

  • 061402 -

PubMed ID

  • 19256836

Electronic International Standard Serial Number (EISSN)

  • 1550-2376

International Standard Serial Number (ISSN)

  • 1539-3755

Digital Object Identifier (DOI)

  • 10.1103/physreve.78.061402

Language

  • eng