Multiscale Modeling of Electronic Polarization Effects in Interfacial Thermodynamics and Nanoscale Transport Phenomena

Abstract

Molecular simulations, along with the tools of statistical mechanics, can provide essential mechanistic insights about the thermodynamic and transport properties of electrolytes at solid/water interfaces, which has broad applications in several scientific disciplines ranging from membrane science to biophysics and electrochemistry. At any solid/water interface, water being a polar solvent and salt ions being charged species, can exert strong electric fields which can in turn result in a significant electronic polarization of the solid. However, a fundamental understanding of the role of electronic polarization effects on interfacial thermodynamics and nanoscale transport has been largely lacking. Moreover, due to the vectorial nature of the electric fields, the ion-solid and water-solid polarization energies, which result from the ion-induced and the water-induced electronic polarization of the solid, respectively, are strictly pair-wise non-additive and many-body in nature. Therefore, a theoretical framework is required which can self-consistently model the polarization energies at solid/water interfaces. In this thesis, a multiscale approach involving quantum chemical and classical molecular dynamics (MD) simulations is advanced to investigate the role of electronic polarization effects, first at planar solid/water interfaces, and subsequently under nanoscale confinement, using 2D and 1D graphitic nanomaterials as model systems. By investigating the wetting of graphitic surfaces, the thermodynamics of salt ion adsorption, and the confined water and salt ion transport through carbon nanotubes, this thesis underscores the broad relevance of electronic polarization effects in interfacial phenomena.