Abstract
Molecular dynamics simulations are carried out in order to investigate the saturation pressure of the water molecules in nanocylinder and to verify the Kelvin equation. Water molecules represented by the TIP4P/2005 model are confined in the nanocylinders whose diameters are 2.2 nm to 5.2 nm. The Lennard-Jones (LJ) potential is employed to model the interaction between a water molecule and a wall atom. The hydrophobic, intermediate, and hydrophilic nanocylinders with different LJ energy parameter are constructed. All of the systems are equilibrated by the constant temperature method in 1 ns. For the nanocylinders with the diameter of 2.2 nm, the Kelvin equation as the function of the temperature is qualitatively consistent to the MD results. When the temperature is fixed to 400 K, the Kelvin equation quantitatively coincides to the MD results for the nanocylinders with the diameter of 4.2 and 5.2 nm in the case of the intermediate and hydrophilic nanocylinders. The discrepancy increases with the decrease of the diameter to 2.2 nm. In the case of the hydrophobic nanocylinder, the Kelvin equation underestimates the saturation pressure.
