Issue
EPL
Volume 80, Number 6, December 2007
Article Number 66002
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/80/66002
Published online 19 November 2007
EPL, 80 (2007) 66002
DOI: 10.1209/0295-5075/80/66002

Contact line stability of ridges and drops

S. Mechkov1, 2, G. Oshanin1, M. Rauscher3, 4, M. Brinkmann5, A. M. Cazabat2 and S. Dietrich3, 4

1  Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie Tour 24, Boîte 121, 4 place Jussieu, F-75252 Paris 05, France
2  Laboratoire de Physique Statistique de l'Ecole Normale Supérieure - 24 rue Lhomond, F-75231 Paris 05, France
3  Max-Planck-Institut für Metallforschung - Heisenbergstr. 3, D-70569 Stuttgart, Germany
4  Institut für Theoretische und Angewandte Physik, Universität Stuttgart - Pfaffenwaldring 57, D-70569 Stuttgart, Germany
5  Max-Planck-Institut für Dynamik und Selbstorganisation - Bunsenstr. 10, D-37073 Göttingen, Germany

rauscher@mf.mpg.de

received 24 July 2007; accepted in final form 23 October 2007; published December 2007
published online 19 November 2007

Abstract
Within the framework of a semi-microscopic interface displacement model in the small slope approximation we analyze the linear stability of sessile ridges and drops of a non-volatile liquid on a homogeneous, partially wet substrate, for both signs and arbitrary amplitudes of the three-phase contact line tension. Focusing on perturbations which correspond to deformations of the three-phase contact line, we find that drops are generally stable while ridges are subject only to the long-wavelength Rayleigh-Plateau instability leading to a breakup into droplets, in contrast to the predictions of capillary models which take line tension into account. We argue that the short-wavelength instabilities predicted within the framework of the latter macroscopic capillary theory occur outside its range of validity and thus are spurious.

PACS
68.15.+e - Liquid thin films.
68.03.Cd - Surface tension and related phenomena.
68.03.-g - Gas-liquid and vacuum-liquid interfaces.

© EPLA 2007