Publication detailsUnderwood, Thomas R. & Greenwell, H. Chris (2018). The Water-Alkane Interface at Various NaCl Salt Concentrations: A Molecular Dynamics Study of the Readily Available Force Fields. Scientific Reports 8: 352.
- Publication type: Journal Article
- ISSN/ISBN: 2045-2322 (electronic)
- DOI: 10.1038/s41598-017-18633-y
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
In this study, classical molecular dynamic simulations have been used to examine the molecular properties of the water-alkane interface at various NaCl salt concentrations (up to 3.0 mol/kg). A variety of different force field combinations have been compared against experimental surface/interfacial tension values for the water-vapour, decane-vapour and water-decane interfaces. Six different force fields for water (SPC, SPC/E, TIP3P, TIP3Pcharmm, TIP4P & TIP4P2005), and three further force fields for alkane (TraPPE-UA, CGenFF & OPLS) have been compared to experimental data. CGenFF, OPLS-AA and TraPPE-UA all accurately reproduce the interfacial properties of decane. The TIP4P2005 (four-point) water model is shown to be the most accurate water model for predicting the interfacial properties of water. The SPC/E water model is the best three-point parameterisation of water for this purpose. The CGenFF and TraPPE parameterisations of oil accurately reproduce the interfacial tension with water using either the TIP4P2005 or SPC/E water model. The salinity dependence on surface/interfacial tension is accurately captured using the Smith & Dang parameterisation of NaCl. We observe that the Smith & Dang model slightly overestimates the surface/interfacial tensions at higher salinities (>1.5 mol/kg). This is ascribed to an overestimation of the ion exclusion at the interface.