Energetic contribution to hydration shells in one-dimensional aqueous electrolyte solution by anomalous hydrogen bonds.

The hydration structure of NaCl aqueous solution was elucidated in carbon nanotubes (CNTs) on the basis of canonical ensemble Monte Carlo simulations. Hydration shells were preferentially formed even in narrow CNTs to gain stabilization energy, whereas hydrogen bonding between water molecules in such CNTs was sacrificed. Nanoscale-confined aqueous electrolyte solutions therefore prioritize hydration shell formation between ions and water rather than hydrogen-bond formation between water molecules.