Berlin 2015 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 33: Critical Phenomena and Phase Transitions
DY 33.12: Vortrag
Mittwoch, 18. März 2015, 18:00–18:15, BH-N 334
Line contribution to the critical Casimir force between a homogeneous and a chemically stepped surface — •Francesco Parisen Toldin1, Matthias Tröndle2,3, and Siegfried Dietrich2,3 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — 2Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany — 3IV. Institut für Theoretische Physik, Universität Stuttgart, Germany
Recent experimental realizations of the critical Casimir effect have been implemented by monitoring colloidal particles immersed in a binary liquid mixture near demixing and exposed to a chemically structured substrate consisting of stripes with alternating adsorption preferences, forming chemical steps between them. We analyze the contribution of such chemical steps to the critical Casimir force for the film geometry and within the Ising universality class. By means of Monte Carlo simulations, mean-field theory, and finite-size scaling analysis we determine the universal scaling function associated with the contribution to the critical Casimir force due to individual, isolated chemical steps facing a surface with homogeneous adsorption preference or with Dirichlet boundary condition. These results allow one to compute the critical Casimir force in the presence of arbitrarily shaped, but wide stripes as a sum of the contributions due to the homogeneous parts of the surface and due to the chemical steps between the stripes. We assess this decomposition by comparing the resulting sum with actual simulation data in the presence of a chemically striped substrate.
Ref: F. Parisen Toldin, M. Tröndle, S. Dietrich, arXiv:1409.5536