Controlling structural organization of binary phase-separating fluids through mobile particles

The structural organization in binary immiscible fluids is studied in the presence of mobile particles. We show that the particles, which are included in the favorable phase due to a selective affinity and assemble therein, can drive the favorable phase to self-organize into cluster, interconnected, and network structures, depending on the particle concentration. The detailed studies enable us to confirm the physical origin of the morphology transitions: At low particle concentration, the assembly of particles would amplify the spatial heterogeneity by depleting the favorable phase in the particle-free region, where the hydrodynamic flows further accelerate the dropletlike formation of favorable phase; with increasing the particle concentration, the assembly of particles becomes energetically unfavorable due to the considerably excluded volume effect of particles and they tend to stabilize the percolated structure of the favorable phase. Furthermore, the respective crossover behaviors of the growth dynamics are also observed, corresponding to different structure formations. (C) 2002 American Institute of Physics.