Phase Separation in a Simple Model with Dynamical Asymmetry

TL;DR

This paper uses computer simulations of a phase separation model with dynamical asymmetry to explore morphological evolution, revealing similarities to viscoelastic phase separation and analyzing scaling behaviors over time.

Contribution

It introduces a Cahn-Hilliard model with order parameter-dependent mobility to study the effects of dynamical asymmetry on phase separation morphology.

Findings

Minority phase domains form percolating structures that shrink and disconnect over time.

Domain growth follows L(t) ~ t^{1/3} in late stages.

Dynamical scaling is violated initially but restored at late times, with the scaling function depending on asymmetry.

Abstract

We perform computer simulations of a Cahn-Hilliard model of phase separation which has dynamical asymmetry between the two coexisting phases. The dynamical asymmetry is incorporated by considering a mobility function which is order parameter dependent. Simulations of this model reveal morphological features similar to those observed in viscoelastic phase separation. In the early stages, the minority phase domains form a percolating structure which shrinks with time eventually leading to the formation of disconnected domains. The domains grow as L(t) ~ t^{1/3} in the very late stages. Although dynamical scaling is violated in the area shrinking regime, it is restored at late times. However, the form of the scaling function is found to depend on the extent of dynamical asymmetry.