Asymmetric Hydrogen Bonding and Orientational Ordering of Water at Hydrophobic and Hydrophilic Surfaces: A Comparison of Water/Vapor, Water/Talc, and Water/Mica Interfaces

Abstract

Interfaces involving aqueous fluid phases play critical roles in natural and technologically important systems, and the atomic scale differences between interfaces involving hydrophobic and hydrophilic substrates are essential to understanding and manipulating their chemical and physical properties. This paper compares computational molecular dynamics results for the atomic density profiles, H-bonding configurations, and orientational ordering of water molecules at three different and illustrative interfaces. These are the free liquid water surface, which can be considered hydrophobic, and the interfaces of liquid water with talc (001) and muscovite (001) surfaces, which are prototypical hydrophobic and hydrophilic inorganic oxide surfaces, respectively. The results clearly demonstrate the importance of substrate structure and composition in controlling interfacial behavior and illustrate the differences between the vapor interface and those involving solids. The atomic density profiles of water at the so...