Self-assembling morphology induced by nanoscale rods in a phase-separating mixture.

A symmetric binary mixture containing mobile nanoscale rods is quenched from a one-phase state into an unstable phase-separating region. Incorporating the motion of rods, the system undergoes spinodal decomposition to form a dropletlike structure. The rod-rod interaction and the preferential adsorption of one of the two immiscible phases onto the mobile rods play an important role in driving the system to self-assemble into this special structure. Within each cluster of the wetting phase, the rods align parallel to each other as in a nematic liquid crystal, while the rod orientations between these clusters are randomly distributed. However, an interconnected structure is recovered in the presence of hydrodynamic interaction. In the present phase-separating mixture with rods, the growth dynamics is examined in detail, and our simulations reveal a crossover from a rod-mobility-dependent to an independent regime. The system always exhibits slowing-down growth behavior where the well-known diffusive Lifshitz-Slyozov mechanism and hydrodynamic effects are both suppressed.