Effects of ion concentration and solvent composition on the properties of water-methanol solutions of NaCl. NPT molecular dynamics computer simulation results

TL;DR

This study uses molecular dynamics simulations to investigate how ion concentration and solvent composition affect the microscopic structure, density, diffusion, and dielectric properties of NaCl in water-methanol solutions.

Contribution

It provides detailed insights into the structural and dynamic properties of NaCl solutions with varying solvent compositions and ion concentrations using advanced simulation models.

Findings

Density varies with solvent composition and ion concentration.

Structural properties such as coordination numbers are affected by solvent mixture.

Self-diffusion coefficients and dielectric constant change with composition.

Abstract

Isothermal-isobaric molecular dynamics simulations are used to examine the microscopic structure and other properties of a model solution consisting of NaCl salt dissolved in water-methanol mixture. The SPC/E water model and the united atom model for methanol are combined with the force field for ions by Dang [J. Amer. Chem. Soc., 1995, 117, 6954] to describe the entire system. Our principal focus is to study the effects of two variables, namely, the solvent composition and ion concentrations on the solution's density, on the structural properties, self-diffusion coefficients of the species and the dielectric constant. Moreover, we performed a detailed analysis of the first coordination numbers of the species. Trends of the behaviour of the average number of hydrogen bonds between solvent molecules are evaluated.