Effect of Nanoporous Confinement on the Compressibility of Water: A Molecular Simulation Study

The thermodynamic properties of fluids confined in nanopores have been shown to differ from those of the bulk (non-confined) fluid. Thermal expansion, freezing point, density, and transport coefficients are all examples of properties affected by nanoconfinement. Of particular interest is the effect of nanoconfinement on a fluid’s elastic properties, which determine the speed of elastic wave propagation through the material. When a porous material is saturated with a fluid, its elasticity is measurably changed. This makes ultrasonic wave propagation an important technique in geophysical characterization to extract information about the presence of fluids in geological porous media. Within the last five years, Dr. Gor's group has examined the thermodynamic properties of nanoconfined fluids, and in particular compressibility, with a main focus on cryogenic liquids (nitrogen, argon, methane). In this research, the methods used in Dr. Gor's group are applied to a study of the compressibility of confined water. This research aims to study the effects of the pore size and the external pressure on the compressibility of water through molecular dynamics and Monte Carlo simulations. An interest in water is justified by the substance’s ubiquity in nature. The effects being studied are currently underexplored, and the results contribute to a better understanding of wave propagation in water-saturated nanoporous media.