Development of Water Reactive Potentials for Sodium Silicate Glasses.

Molecular dynamics (MD) simulations provide important insights into atomistic phenomena and are complement to experimental methods of studying glass-water interaction and glass corrosion. For simulations of glass-water systems using MD, there is a need to for a reactive potential that is capable not only to describe the bulk and surface glass structures but also reactions between glass and water. An important aspect of the glass water interaction is the dissociation of water and its interaction with glass components that can result in the dissolution and alteration in the structure of glass. These phenomena can be efficiently simulated using "Reactive" potentials that allow for the dissociation of water while properly describing the bulk physical properties of water. We demonstrate a method to develop parameters for simulations of sodium silicate glasses and their interactions with bulk water. The developed parameter set was used to simulate sodium silicate glasses of different compositions, and the local structure of the simulated glass is in good compliance with experimentally obtained structural information. We also demonstrate that the parameter set predicts an accurate value for the hydration number and dissociation reactions of NaOH in water. Based on these results, we posit that these simple and computationally efficient reactive potentials can be used for further studies of water-induced structural modifications in sodium silicate glasses.