Issue
EPL
Volume 88, Number 4, November 2009
Article Number 40004
Number of page(s) 6
Section General
DOI http://dx.doi.org/10.1209/0295-5075/88/40004
Published online 27 November 2009
EPL, 88 (2009) 40004
DOI: 10.1209/0295-5075/88/40004

Normal and lateral critical Casimir forces between colloids and patterned substrates

M. Tröndle, S. Kondrat, A. Gambassi, L. Harnau and S. Dietrich

Max-Planck-Institut für Metallforschung - Heisenbergstr. 3, D-70569 Stuttgart, Germany, EU Institut für Theoretische und Angewandte Physik, Universität Stuttgart - Pfaffenwaldring 57, D-70569 Stuttgart, Germany, EU


received 6 August 2009; accepted in final form 28 October 2009; published November 2009
published online 27 November 2009

Abstract
We study the normal and lateral effective critical Casimir forces acting on a spherical colloid immersed in a critical binary solvent and close to a chemically structured substrate with alternating adsorption preference. We calculate the universal scaling function for the corresponding potential and compare our results with recent experimental data (SOYKA F., ZVYAGOLSKAYA O., HERTLEIN C., HELDEN L. and BECHINGER C., Phys. Rev. Lett.,101 (2008) 208301). The experimental potentials are properly captured by our predictions only by accounting for geometrical details of the substrate pattern for which, according to our theory, critical Casimir forces turn out to be a sensitive probe.

PACS
05.70.Jk - Critical point phenomena.
82.70.Dd - Colloids.
68.35.Rh - Phase transitions and critical phenomena.

© EPLA 2009