Solvation of complex surfaces via molecular density functional theory

TL;DR

This paper demonstrates that classical molecular density functional theory (MDFT) can efficiently and accurately model the solvation of complex surfaces by polar solvents, matching detailed simulations at a fraction of the computational cost.

Contribution

The study introduces MDFT as a powerful, efficient tool for molecular-level solvation analysis of complex surfaces, with systematic insights into surface-solvent interactions.

Findings

MDFT achieves similar accuracy to all-atom simulations.

The method reduces computational time by two orders of magnitude.

Surface solvent structure depends weakly on atomic charge distribution.

Abstract

We show that classical molecular density functional theory (MDFT), here in the homogeneous reference fluid approximation in which the functional is inferred from the properties of the bulk solvent, is a powerful new tool to study, at a fully molecular level, the solvation of complex surfaces and interfaces by polar solvents. This implicit solvent method allows for the determination of structural, orientational and energetic solvation properties that are on a par with all-atom molecular simulations performed for the same system, while reducing the computer time by two orders of magnitude. This is illustrated by the study of an atomistically-resolved clay surface composed of over a thousand atoms wetted by a molecular dipolar solvent. The high numerical efficiency of the method is exploited to carry a systematic analysis of the electrostatic and non-electrostatic components of the surface-solvent interaction within the popular CLAYFF force field. Solvent energetics and structure are found to depend weakly upon the atomic charges distribution of the clay surface, even for a rather polar solvent. We conclude on the consequences of such findings for force-field development.