Dynamics of Concentration Fluctuation on Both Sides of Phase Boundary

Phase separation kinetics of binary polymer mixtures has become an increasingly interested subject in recent years because of its fundamental and practical importance1–9. The Cahn-Hilliard10 or Cahn-Hilliard-Cook11 theory has generally been used in the analysis of experimental data, but the results are still not conclusive. For example: the importance of the thermal fluctuation during spinodal decomposition and a quantitative comparison of the interfacial free energy density between experiment and theory are still unsettled topics, let alone the more subtle question of the nature of the instability.