Dielectric Properties of Water with a Low Quantity of NaCl inside Charged Nanoslits.

Abstract

A 0.5 molal solution of NaCl in water confined within charged graphene nanoslits represents an intriguing system for molecular dynamics simulation, functioning as a model for a nanocapacitor. This charged configuration not only holds practical significance for the advancement of nanoscale capacitors but also offers valuable insights into how the charged walls and applied electric field influence the structure of water, the movement of ions within the solution, and how these alterations in water impact the overall fluid behavior. The behavior of the solution under nanoconfinement diverges markedly from that observed in bulk conditions, exhibiting distinct structural, dynamic, and dielectric properties. The charging of the graphene nanoslits generates an electric field within the nanopore, which plays a critical role in modulating molecular interactions. Key properties, including the static dielectric constant, polarization, and density of the 0.5 molal solution, are systematically examined through the molecular structure of the confined system. The models employed in this study include the flexible FAB/ϵ model of water, which effectively reproduces various experimental properties of water under different pressure and temperature conditions. Additionally, the NaCl/ϵ model is used, which also captures a range of experimental characteristics associated with sodium chloride solutions. Together, these models facilitate a comprehensive understanding of the complex behavior of water and ions under the influence of nanoconfinement and electric fields, providing insights that are essential for both fundamental science and practical applications in nanotechnology.