Wetting Properties of Clathrate Hydrates in the Presence of Polycyclic Aromatic Compounds: Evidence of Ion-Specific Effects

Polycyclic aromatic hydrocarbons (PAHs) have attracted remarkable multidisciplinary attention due to their intriguing pi-pi stacking configurations, showing enormous opportunity for their use in a variety of advanced applications. To secure progress, detailed knowledge on PAHs' interfacial properties is required. Employing molecular dynamics, we probe the wetting properties of brine droplets (KCl, NaCl, and CaCl2) on sII methane-ethane hydrate surfaces immersed in various oil solvents. Our simulations show synergistic effects due to the presence of PAHs compounded by ion-specific effects. Our analysis reveals phenomenological correlations between the wetting properties and a combination of the binding free-energy difference and entropy changes upon oil solvation for PAHs at oil/brine and oil/hydrate interfaces. The detailed thermodynamic analysis conducted upon the interactions between PAHs and various interfaces identifies molecular-level mechanisms responsible for wettability alterations, which could be applicable for advancing applications in optics, microfluidics, medicine, as well as

Automated summary

Polycyclic aromatic hydrocarbons (PAHs) have captured significant attention due to their unique stacking configurations, offering great opportunities for advanced applications. In this study, molecular dynamics simulations were conducted to investigate the wetting properties of brine droplets on methane-ethane hydrate surfaces in various oil solvents. The results demonstrated synergistic effects of PAHs and ion-specific effects on wetting properties. Thermodynamic analysis revealed correlations between wetting properties and the combination of binding free-energy difference and entropy changes. Molecular-level mechanisms responsible for wettability alterations were identified, which could be relevant for advancements in optics, microfluidics, medicine, and other applications.