Tuesday, July 9, 2013

1307.2070 (Markus Bier et al.)

Non-equilibrium interfaces in colloidal fluids    [PDF]

Markus Bier, Daniel Arnold
The time-dependent structure, interfacial tension, and evaporation of an oversaturated colloid-rich (liquid) phase in contact with an undersaturated colloid-poor (vapor) phase of a colloidal dispersion is investigated theoretically. Since systems of this type exhibit a clear separation of colloidal and solvent relaxation time scales with typical times of interfacial tension measurements in between, they can be expected to be suitable for analogous experimental studies, too. The major observation is that, irrespective of how much the bulk phases differ from two-phase coexistence, the interfacial structure and the interfacial tension at long times approach those at two-phase coexistence. Scaling forms for the long-time asymptotics of the local chemical potential, the flux, and the dissipation rate exhibit qualitatively different leading order contributions depending on whether an equilibrium or a non-equilibrium system is considered. The degree of non-equilibrium between the bulk phases is found to not influence the qualitative relaxation behavior (i.e., the values of power-law exponents), but to determine the quantitative deviation of the observed quantities from their values at two-phase coexistence. Whereas the underlying dynamics differs between colloidal and molecular fluids, the long-time behavior of quantities such as the interfacial tension approaching the equilibrium values even under non-equilibrium conditions can be expected to occur for both types of systems.
View original: http://arxiv.org/abs/1307.2070

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