title: Rayleigh and depinning instabilities of forced liquid ridges on heterogeneous substrates.
abstract: Depinning of two-dimensional liquid ridges and three-dimensional drops on an inclined substrate is studied within the lubrication approximation. The structures are pinned to wetting heterogeneities arising from variations of the strength of the short-range contribution to the disjoining pressure. The case of a periodic array of hydrophobic stripes transverse to the slope is studied in detail using a combination of direct numerical simulation and branch-following techniques. Under appropriate conditions the ridges may either depin and slide downslope as the slope is increased, or first break up into drops via a transverse instability, prior to depinning. The different transition scenarios are examined together with the stability properties of the different possible states of the system.
authors.affiliation: UMR EmmaH 1114, Département de Physique, Université d'Avignon, F-84000 Avignon, France. philippe.beltrame@univ-avignon.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Beltrame
authors.forename: Edgar
authors.initials: E
authors.lastname: Knobloch
authors.forename: Peter
authors.initials: P
authors.lastname: Hänggi
authors.forename: Uwe
authors.initials: U
authors.lastname: Thiele