Coarsening and Pinning in the Self-consistent Solution of Polymer Blends Phase-Separation Kinetics

TL;DR

This paper analytically investigates phase-separation kinetics in binary polymer blends using a continuum model, revealing complex intermediate regimes, pinning phenomena, and late-stage dynamics with scaling laws.

Contribution

It introduces an analytical approach to study phase separation in polymer blends, highlighting pinning effects and crossover behaviors in different segregation limits.

Findings

Pinning of phase separation occurs in deep quenches.

Pinning duration diverges in the strong segregation limit.

Late-stage dynamics follow scaling laws similar to small molecule systems.

Abstract

We study analytically a continuum model for phase-separation in binary polymer blends based on the Flory-Huggins-De Gennes free energy, by means of the self-consistent large-$n$ limit approach. The model is solved for values of the parameters corresponding to the weak and strong segregation limits. For deep quenches we identify a complex structure of intermediate regimes and crossovers characterized by the existence of a time domain such that phase separation is pinned, followed by a preasymptotic regime which in the scalar case corresponds to surface diffusion. The duration of the pinning is analytically computed and diverges in the strong segregation limit. Eventually a late stage dynamics sets in, described by scaling laws and exponents analogous to those of the corresponding small molecule systems.