Thermodynamic characteristics of the hydrate shell of a Na+ ion in a plane nanopore with hydrophobic walls

The chemical potential, free energy, and work of hydration of a single-charged sodium cation are calculated using the Monte Carlo method for a bicanonic statistic ensemble at the molecular level at 298 K in plane model nanopores 0.5 and 0.7 nm wide. It is shown that the nanopores have a stabilizing effect on the hydrate shell of an ion. It is concluded that the crisis of stability that occurs outside a pore is transformed into an abrupt acceleration of growth with the conservation of a stable equilibrium with vapor under the conditions of plane nanopores. It is established that the mechanism of the threshold acceleration of growth inside a pore is associated with an ion being displaced from its own hydrate shell.