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DY: Fachverband Dynamik und Statistische Physik

DY 29: Spatially Extended Dynamical Systems

DY 29.4: Vortrag

Donnerstag, 25. März 2010, 14:45–15:00, H46

Substrate Mediated Condensation and Pattern Formation in Thin Liquid Films — •Michael H. Köpf, Svetlana V. Gurevich, and Rudolf Friedrich — Institute for Theoretical Physics, University of Münster, Wilhelm-Klemm-Straße 9, D-48149 Münster

The formation of regular stripe patterns during transfer of surfactant monolayers onto solid substrates is investigated. Two coupled differential equations describing the surfactant density and the height profile of the water subphase are derived within the long-wavelength approximation. If the transfer is carried out in the vicinity of a surfactant first-order phase transition, the interaction with the substrate plays a key role. This effect is included in the surfactant free-energy functional via a height dependent external field. Using transfer velocity and lateral pressure as control parameters a bifurcation from a homogeneous transfer to regular stripe patterns arranged parallel to the contact line is investigated in one and two dimensions. Moreover, in the two-dimensional case a secondary bifurcation to perpendicular stripes is observed in a certain control parameter range.