Crossover in growth law in the vapor-liquid phase separation inside complex porous medium

TL;DR

This study uses molecular dynamics simulations to explore how vapor-liquid phase separation dynamics change within complex porous media, revealing a crossover from classical power-law growth to a slower, logarithmic regime due to confinement effects.

Contribution

It demonstrates the existence of a crossover in domain growth laws inside porous media and links this transition to pore size and geometry effects.

Findings

Breakdown of Porod law and fractal domain boundaries

Crossover from power-law to logarithmic growth regimes

Quantitative scaling relation between growth behavior and pore size

Abstract

We employ molecular dynamics simulations to investigate the domain morphology and growth kinetics of a vapor-liquid system embedded within a complex porous medium. By systematically varying the pore structure, we analyze the scaling behavior of correlation functions, structure factors, and domain growth exponents. The structure factor confirms the breakdown of Porod law and the emergence of fractal-like domain boundaries. Our key finding is the clear crossover in the domain growth law, from the classical power-law behavior observed in bulk fluids to a slower, logarithmic regime in highly confined systems. This transition is driven by energy barriers introduced by the porous geometry, which inhibit coarsening dynamics at later time. We provide a scaling analysis which further confirms this crossover and quantitatively connects the growth behavior with the average pore size.