Molecular Dynamics Studies of Interfacial Water at the Alumina Surface

Abstract

Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to ∼10 A from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior at distances greater than ∼10 A from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water−water interactions on the structural properties at the interface.