Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: SYMPOSIUM Driven Soft Matter IV

CPP 19.6: Vortrag

Mittwoch, 27. Februar 2008, 15:15–15:30, C 130

Bridging scales in a phase separating binary fluid: From Cahn-Hilliard to Doi-Ohta model — •Asja Jelić, Patrick Ilg, and Hans Christian Öttinger — ETH Zurich, Department of Materials, Polymer Physics, CH-8093, Switzerland

Mixtures of immiscible fluids are systems that can be studied at various length and time scales. The General Equation for the Non-Equilibrium Reversible-Irreversible Coupling (GENERIC) framework is used to connect two different levels of description of a phase separating binary fluid. We start from the Cahn-Hilliard model of spinodal decomposition in a binary fluid mixture under flow from which we derive the coarse-grained description. The familiar Doi-Ohta model is recovered in the long wavelength limit. The key ingredient required for this procedure is a mapping of the variables of one level to another, so that a statistical formulation of GENERIC framework in a generalized mixed ensemble enables one to develop a thermodynamically consistent formulation and simulation algorithms for non-equilibrium systems and sets the framework for their multi-level description. The present state of the study relates the two levels by giving the expected reversible time evolution and shedding new light on the irreversible processes and the interpretation of the parameters in the Doi-Ohta model.