Water in Inhomogeneous Nanoconfinement: Coexistence of Multilayered Liquid and Transition to Ice Nanoribbons

Abstract

Phase behavior and the associated phase transition of water within inhomogeneous nanoconfinement are investigated using molecular dynamics simulations. The nanoconfinement is constructed by a flat bottom plate and a convex top plate. At 300 K, the confined water can be viewed as a coexistence of monolayer, bilayer, and trilayer liquid domains to accommodate the inhomogeneous confinement. With increasing liquid density, the confined water with uneven layers transforms separately into two-dimensional ice crystals with unchanged layer number and rhombic in-plane symmetry for oxygen atoms. The monolayer water undergoes the transition first into a puckered ice nanoribbon, and the bilayer water transforms into a rhombic ice nanoribbon next, followed by the transition of trilayer water into a trilayer ice nanoribbon. The sequential localized liquid-to-solid transition within the inhomogeneous confinement can also be achieved by gradually decreasing the temperature at low liquid densities. These findings of phase behaviors of water under the inhomogeneous nanoconfinement not only extend the phase diagram of confined water but also have implications for realistic nanofluidic systems and microporous materials.

Effect of layered water structures on the anomalous transport through nanoscale graphene channels

“…We find a direct correlation between the formation of layered water structures and the transport properties in the twodimensionally confined channels. The layered structures are similar to the ice-like structures observed under nanoscale confinement in earlier studies [39][40][41][42][43][44].…”

Dependence of the shape of graphene nanobubbles on trapped substance

“…In contrast to ref. 24, we argue that the density and size of water bubbles are important factors that control the microscopic structure of trapped water which was not considered in other theoretical work16. In the latter study, confined water between two parallel graphene sheets was studied for different interlayer distances (6–12 Å) using MD simulations.…”

“…In common MDs simulations2024, the pressure is calculated using the virial method which requires a homogeneous system1011:…”

Reversible structural transition in nanoconfined ice

“…Later, Wu Zhou et al argued that the above mentioned experiment can be better explained as due to salt (for example, NaCl) contaminants precipitating as nanocrystals between the graphene layers 7 . Notwithstanding the existing MD based theory studies in the past few years, there are still challenging questions such as: how important is the boundary condition in common MD simulations and its consequence on the structural properties of nanoconfined water [8][9][10] . Most of the water phases, e.g.…”