arXiv subjects

Rounak Bhattacharyya

Publications and source records attributed to Rounak Bhattacharyya.

3 recordsLinked to original sources

arXiv2023

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.

cond-mat.soft↗

arXiv2022

Phase separation and aging dynamics of binary liquid in porous media

We employ the state-of-the-art molecular dynamics simulations to study the kinetics of phase separation and aging phenomena of segregating binary fluid mixtures imbibed in porous materials. Different random porous structures are considered to understand the effect of pore morphology on coarsening dynamics. We find the effect of complex geometrical confinement resulting in the dramatic slowing down in the phase separation dynamics. The domain growth follows the power law with an exponent dependent on the porous host structure. After the transient period, a crossover to a slower domain growth is observed when the domain size becomes comparable to the pore size. Due to the geometric confinement, the correlation function and structure factor modify to a non-Porod behavior and violate the superuniversality hypothesis. The role of porous host structure on the nonequilibrium aging dynamics is studied qualitatively by computing the two-time order-parameter autocorrelation function. This quantity exhibits scaling laws with respect to the ratio of the domain length at the observation time and the age of the system. We find the scaling laws hold good for such confined segregating fluid mixtures.

cond-mat.soft↗

arXiv2021

Effect of Annealed Disorder on Phase Separation Kinetics and Aging Phenomena in Fluid Mixtures

We use state-of-the-art molecular dynamics simulations to study the effects of annealed disorder on the phase separating kinetics and aging phenomena of a segregating binary fluid mixture. In the presence of disorder, we observe a dramatic slowing down in the phase separation dynamics. The domain growth follows the power-law with a disorder-dependent exponent. Due to the energetically favorable positions, the domain boundary roughens which modifies the correlation function and structure factor to a non-Porod behavior. The correlation function and structure factor provide clear evidence that the superuniversality does not hold in our system. The role of annealed disorder on the non-equilibrium aging dynamics is studied qualitatively by computing the two-time order parameter autocorrelation function. The decay of the correlation function slows down significantly with the disorder. This quantity exhibits scaling laws with respect to the ratio of the domain length at the observation time and the age of the system. We find the scaling laws hold good for the disordered system and therefore, robust and generic to such segregating fluid mixtures.

cond-mat.soft↗