Incollection,
Instabilities and pattern formation in phase-separating fluids
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)
Abstract
The thermodynamic equilibrium of fluid mixtures and their isothermal
relaxation to equilibrium after a rapid temperature quench are well
understood due to extensive experimental, numerical and theoretical
studies in the past decades. In many technological and natural
processes one is however confronted with phase-separating systems
where the temperature is slowly drifting. In this case it is of
interest to follow the evolution of the (local) composition also while
the temperature is evolving. A simple estimate shows that even for
very small drift the composition cannot quasi-statically (in the sense
of local thermodynamic equilibrium) follow the change of
temperature. The temporal evolution of the composition consequently
becomes a problem of pattern formation: For small temperature drift
convection arises, and a large drift induces repeated waves of
precipitation.
We derive a phase diagram accounting for the cross-over between the
quasi-static, convective and oscillatory regimes, and present a
minimal theoretical model addressing the parameter dependence of the
oscillations. The latter agrees well with recent experimental data.
References:\\
Auernhammer, D. Vollmer, J. Vollmer, J. Chem. Phys. 123, 134511 (2005).\\
J. Vollmer, Auernhammer, D. Vollmer, Phys. Rev. Lett. 98, 115701 (2007).
