On the composition dependence of the microscopic structure, thermodynamic, dynamic and dielectric properties of water-dimethyl formamide model mixtures. Molecular dynamics simulation results

TL;DR

This study uses molecular dynamics simulations to analyze how the microscopic structure, thermodynamic, dynamic, and dielectric properties of water-DMF mixtures depend on composition, providing detailed insights into their molecular behavior.

Contribution

It presents comprehensive simulation results on water-DMF mixtures, examining structural, thermodynamic, dynamic, and dielectric properties as a function of composition for the first time.

Findings

Density and excess molar volume vary with composition.

Hydrogen bonding patterns depend on mixture ratio.

Self-diffusion coefficients and dielectric constant are quantified.

Abstract

Isothermal-isobaric molecular dynamics simulations have been performed to examine an ample set of properties of the model water-N,N-dimethylformamide (DMF) mixture as a function of composition. The SPC-E and TIP4P-Ew water models together with two united atom models for DMF [Chalaris M., Samios J., J. Chem. Phys., 2000, 112, 8581; Cordeiro J., Int. J. Quantum Chem., 1997, 65, 709] were used. Our principal analyses concern the behaviour of structural properties in terms of radial distribution functions, and the number of hydrogen bonds between molecules of different species as well as thermodynamic properties. Namely, we explore the density, excess mixing molar volume and enthalpy, the heat capacity and excess mixing heat capacity. Finally, the self-diffusion coefficients of species and the dielectric constant of the system are discussed. In addition, surface tension of water-DMF mixtures has been calculated and analyzed.