Phase separation kinetics of segregating fluid mixtures in the presence of quenched disorder

Quenched or frozen-in structural disorder is ubiquitous in real experimental systems. Much of the progress is achieved in understanding the phase separation of such systems using the diffusion-driven coarsening in Ising model with quenched disorder. But there is a paucity of research in the phase separation kinetics in fluids with quenched disorder. In this paper, we present results from a detailed Molecular dynamics simulation, the effects of randomly placed localized impurities on the phase separating kinetics of binary fluid mixture. Two different models are offered for representing the impurities. We observe a dramatic slowing down in the pattern formation with increasing impurity concentration. This sluggish domain growth kinetics follows power-law with a disorder-dependent exponent. The correlation function and structure factor show a non-Porod behavior, indicating the roughening of domain interfaces. We have also studied the effect of quenched disorder on the aging dynamics by calculating the two-time order parameter auto correlation function and find that the Fisher and Huse scaling law holds good in presence of quenched disorder.

Rounak Bhattacharyya, Bhaskar Sen Gupta · 2021