Coarsening and pattern formation during true morphological phase separation in unstable thin films under gravity

Area of Science:

• Physics
• Materials Science
• Fluid Dynamics

Background:

• Investigates morphological phase separation (MPS) in unstable thin liquid films (>100nm).
• Focuses on systems influenced by gravity, featuring asymmetric free-energy functionals.
• Highlights the formation of two equilibrium phases due to common tangency points.

Purpose of the Study:

• To detail true morphological phase separation (MPS) in three-dimensional thin liquid films.
• To identify distinct patterns and understand pattern formation dynamics.
• To analyze phase-ordering dynamics and growth laws under gravitational influence.

Main Methods:

• Utilizes statistical measures including structure factor and correlation function.
• Examines pattern formation and phase-ordering dynamics.
• Applies growth law analysis to characterize domain size evolution.

Main Results:

• Identified three distinct patterns in true MPS.
• Revealed two pathways for pattern formation: defect and direct.
• Observed Lifshitz-Slyozov growth law [L(t)∼t^{1/3}] in the late stage, with a crossover [L(t)∼t^{1/4}→t^{1/3}] in the defect pathway's dynamical scaling regime.

Conclusions:

• Asymmetric free-energy functionals drive distinct pattern formation mechanisms in thin liquid films.
• Phase-ordering dynamics exhibit universal scaling behavior, with pathway-specific crossovers.
• Provides insights into analogies and differences between MPS and spinodal phase separation.