A thermodynamic description of coupled flow and diffusion in a viscoelastic binary mixture

We use an irreversible thermodynamics approach to derive hydrodynamic equat ions which govern the flow-induced concentration changes produced by inhomo geneous stresses in a viscoelastic binary mixture. The most relevant effect s arising from these inhomogeneous flows are manifested in the migration of the dispersed phase and as flow-induced concentration fluctuations. Couple d constitutive equations for the mass flux and the stress tensor are derive d self-consistently from our formalism. We show that our approach is consis tent with different existing isothermal formalisms which predict the growth of concentration fluctuations and shear-induced diffusion of mass. Finally , we also comment on the possibility of extending our approach to incorpora te nonisothermal effects and on the limitations and advantages of our descr iption.