(671e) Curvature Dependence of Henry's Law Constant and Non-Ideality of Gas Equilibrium for Highly Curved Vapor-Liquid Interfaces

Curved interfaces between coexisting vapor and liquid phases are ubiquitous in nature. The recently confirmed existence of surface/bulk nanobubbles raises the question of whether the law is applicable for highly curved vapor/liquid (VL) interfaces. By combining molecular dynamics simulations and thermodynamic analysis, we investigated the applicability of Henry's law for highly curved VL interfaces. In general, the Henry’s law could not be used directly for nanobubbles that have highly curved vapor-liquid interfaces. Instead, the Henry’s law constant exhibits a novel curvature dependence, which is ascribed to the non-ideality of gas in liquid phase because of the required gas supersaturation for stabilizing the nanobubbles. To account for this effect, we developed a method for the determination of the Henry’s law constant from the level of gas supersaturation. With the modifed Henry’s law, we trun to vapor/liquid equilibrium and gas partitioning across highly curved VL interfaces. Again, the non-ideality of gas in liquid significantly changes the relationship between gas supersaturation and nanobubble radius. Our findings can provide guidance for determining the gas partitioning of nanobubbles and explaining its unusual phase equilibrium behaviors.