Dresden 2003 – scientific programme
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DY: Dynamik und Statistische Physik
DY 22: Soft matter II
DY 22.4: Talk
Tuesday, March 25, 2003, 11:30–11:45, G\"OR/226
Templating by chemical structuring: Coarsening vs. Pinning — •Uwe Thiele1, Lutz Brusch1, Michael Bestehorn2, and Markus Bär1 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, D-01187 Dresden — 2Lehrstuhl für Statistische Physik und Nichtlineare Dynamik,BTU-Cottbus, Erich-Weinert-Strasse 1, 03046 Cottbus
The dewetting of a very thin liquid film is studied on a substrate (template) that is chemically patterned on the nanometer scale. The conditions for the amplitude and periodicity of the heterogeneity that allow to ideally impose the substrate pattern onto the structure of liquid emerging from the dewetting process are analysed using a thin film evolution equation incorporating a spatially varying disjoining pressure.
Using as an example a periodically striped substrate bifurcation and stability analysis of the possible liquid ridge solutions reveal parameter ranges where pinning or coarsening ultimately prevail. We also identify an extendet parameter range of multistability of the different morphologies. There the selected pattern depends strongly on the initial constellation and potential finite perturbations in the system as we illustrate with numerical integrations in time.
Finally, the instability with respect to transversal modes leading to a decay of the ridges into rows of drops is discussed for the pinned solution and it is shown that it may render the parameter range where the liquid film images ideally the template.