Crossover from the hydrodynamic regime to the thermal fluctuation regime in a two-dimensional phase-separating binary fluid containing surfactants

Jiunn-Ren Roan, Chin-Kun Hu
2000 Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics  
Extensive simulations were carried out to investigate the crossover between the hydrodynamic regime at intermediate stage and the thermal fluctuation regime at late stage in a phase-separating binary fluid/surfactant system in two dimensions. The existence of the crossover and its dependence on the surfactant concentration were analyzed using Kawasaki and Ohta's interface kinetic equation ͓Physica A 118, 175 ͑1983͔͒. The analysis showed that there should exist a critical surfactant
more » ... actant concentration, above which thermal fluctuations dominate phase separation at all times. Simulations suggested that the crossover exists and the hydrodynamic regime shrinks when surfactant concentration increases. Simulations also demonstrated that the trapped surfactants seen in a previous study ͓Phys. Rev. E 59, 2109 ͑1999͔͒ can remain trapped for a time much longer than the time needed to form well segregated domains, in spite of the presence of significant thermal fluctuations.
doi:10.1103/physreve.62.766 pmid:11088532 fatcat:3hi4mpxwv5gohemvkleykgnoxa