Phase segregation in a binary fluid confined inside a nanopore

Abstract

Using a hydrodynamics preserving thermostat, we present extensive molecular dynamics simulation results for the kinetics of phase separation in a model binary fluid confined inside a cylindrical nanopore with neutral wall. We observe the formation of a striped pattern, where A-rich and B-rich domains appear alternately along the axis of the cylinder. For a wide range of diameters of the cylinders, the growth of the pattern freezes and does not lead to complete phase separation. Prior to freezing, the growth of these stripes passes through two power-law regimes. The early-time regime is related to the Lifshitz-Slyozov diffusive mechanism and the estimated value of the exponent for the later-time regime matches well with that for the inertial hydrodynamic growth in three-dimensional fluid systems. Appropriate arguments have been provided to justify the observations. Furthermore, our results show that the length of the cylinder does not seem to affect the average axial length of the frozen patterns. However, the latter exhibits a linear dependence on the diameter of the cylinder.