2015-09-16
10:15 at HCI J 574

Nonequilibrium Thermodynamics Approach to Interfacial Transport Phenomena

Meisam Pourali

Department of Physical Chemistry, University of Tehran, Iran

The dynamic properties of interfaces often play a crucial role in the macroscopic dynamics of multiphase soft condensed matter systems. These properties affect the dynamics of many phenomena such as emulsions, dispersions of vesicles, biological fluid, free surface flows, immiscible polymer blends, and dynamics of many other complex systems. In the description of transport through and along interfaces using nonequilibrium thermodynamics, one may use excess densities, fluxes, and also structural variables at the so-called dividing surface. But the precise choice of the location of this dividing surface within the interfacial region is not unique and density of conserved quantities change with the precise location of the dividing surface within the interfacial region. So balancing of corresponding extensive quantities at interfaces in terms of excess densities is ambiguous. Recently Ottinger and Venerus [HC Öttinger and DC Venerus, AIChE Journal 60 (4), 1424-1433 (2014) (and references therein)] proposed a method to handle such ambiguities for moving interfaces. In this seminar this method is presented. First we introduce the interfacial velocity and principle of gauge transformation to establish relationships between bulk phase thermodynamic quantities and to identify relevant thermodynamic quantities of the moving interface. Then we formulate jump balance for mass and momentum and evolution equations of entropy and energy. With local equilibrium assumption we obtain an expression for entropy production and then we are able to formulate force-fluxes relations, constitutive equations, for transport both within the interface and between the interface and bulk. Finally usefulness and generality of this approach is illustrated by several examples.