Issue 42, 2015

Colloidal binary mixtures at fluid–fluid interfaces under steady shear: structural, dynamical and mechanical response

Abstract

We experimentally study the link between structure, dynamics and mechanical response of two-dimensional (2D) binary mixtures of colloidal microparticles spread at water/oil interfaces. The particles are driven into steady shear by a microdisk forced to rotate at a controlled angular velocity. The flow causes particles to layer into alternating concentric rings of small and big colloids. The formation of such layers is linked to the local, position-dependent shear rate, which triggers two distinct dynamical regimes: particles either move continuously (“Flowing”) close to the microdisk, or exhibit intermittent “Hopping” between local energy minima farther away. The shear-rate-dependent surface viscosity of the monolayers can be extracted from a local interfacial stress balance, giving “macroscopic” flow curves whose behavior corresponds to the distinct microscopic regimes of particle motion. Hopping regions reveal a higher resistance to flow compared to the flowing regions, where spatial organization into layers reduces dissipation.

Graphical abstract: Colloidal binary mixtures at fluid–fluid interfaces under steady shear: structural, dynamical and mechanical response

Supplementary files

Article information

Article type
Paper
Submitted
09 Jul 2015
Accepted
01 Sep 2015
First published
01 Sep 2015

Soft Matter, 2015,11, 8313-8321

Colloidal binary mixtures at fluid–fluid interfaces under steady shear: structural, dynamical and mechanical response

I. Buttinoni, Z. A. Zell, T. M. Squires and L. Isa, Soft Matter, 2015, 11, 8313 DOI: 10.1039/C5SM01693B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements