Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER
CPP 5.20: Poster
Freitag, 4. März 2005, 17:15–19:00, Poster TU D
Dynamical Model for Chemically Driven Running Droplets — •Uwe Thiele1, Karin John1, and Markus Bär1,2 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, D-01187 Dresden, Germany — 2Physikalisch-Technische Bundesanstalt, Abbestrasse 2 - 12, D-10587 Berlin, Germany
Chemically driven self-propelled running droplets are studied employing dynamical models [1]. We use coupled evolution equations for the film thickness profile and the adsorbate coverage of the solid substrate. The film evolution equation includes a disjoining pressure that models the adsorbate dependent wettability. In the adsorbate evolution equation we employ different reaction terms that (a) only allows for adsorption underneath the droplet [1] or (b) allows furthermore for desorption at the ’bare’ substrate. The two models describe different sets of experiments found in the literature [2-4]. Change of the reaction rate or maximal wettability difference allows for qualitatively different regimes of the drop movement corresponding to experimental results [2,3]. Finally, we discuss a model for running droplets whose movement is caused by an ongoing phase transition.
[1] U. Thiele, K. John and M. Bär, Phys. Rev. Lett., 93, 027802 (2004); [2] F. Domingues Dos Santos and T. Ondarcuhu, Phys. Rev. Lett. 75, 2972 (1995); [3] S. W. Lee, D. Y. Kwok, and P. E. Laibinis, Phys. Rev. E 65, 051602 (2002); [4] Y. Sumino et al., to be published (2004).