Issue 13, 2014

Alignment of cylindrical colloids near chemically patterned substrates induced by critical Casimir torques

Abstract

Recent experiments have demonstrated a fluctuation-induced lateral trapping of spherical colloidal particles immersed in a binary liquid mixture near its critical demixing point and exposed to chemically patterned substrates. Inspired by these experiments, we study this kind of effective interaction, known as the critical Casimir effect, for elongated colloids of cylindrical shape. This adds orientational degrees of freedom. When the colloidal particles are close to a chemically structured substrate, a critical Casimir torque acting on the colloids emerges. We calculate this torque on the basis of the Derjaguin approximation. The range of validity of the latter is assessed via mean-field theory. This assessment shows that the Derjaguin approximation is reliable in experimentally relevant regimes, so that we extend it to Janus particles endowed with opposing adsorption preferences. Our analysis indicates that critical Casimir interactions are capable of achieving well-defined, reversible alignments both of chemically homogeneous and of Janus cylinders.

Graphical abstract: Alignment of cylindrical colloids near chemically patterned substrates induced by critical Casimir torques

Article information

Article type
Paper
Submitted
12 Nov 2013
Accepted
05 Dec 2013
First published
10 Feb 2014

Soft Matter, 2014,10, 2270-2291

Alignment of cylindrical colloids near chemically patterned substrates induced by critical Casimir torques

M. Labbé-Laurent, M. Tröndle, L. Harnau and S. Dietrich, Soft Matter, 2014, 10, 2270 DOI: 10.1039/C3SM52858H

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