COARSENING AND PINNING IN THE SELF-CONSISTENT SOLUTION OF POLYMER BLENDS PHASE-SEPARATION KINETICS

We study analytically a continuum model for phase separation in binary polymer blends based on the Flory-Huggins-de Gennes free energy, by m eans of the self-consistent large-rt limit approach. The model is solv ed for values of the parameters corresponding to the weak and strong s egregation limits. For deep quenches we identify a complex structure o f intermediate regimes and crossovers characterized by the existence o f a time domain such that phase separation is pinned, followed by a pr easymptotic regime, which in the scalar case corresponds to surface di ffusion. The duration of the pinning is analytically computed and dive rges in the strong segregation limit. Eventually a late-stage dynamics sets in, described by scaling laws and exponents analogous to those o f the corresponding small-molecule systems.