Composition Effect on Interfacial Reactions of Sodium Aluminosilicate Glasses in Aqueous Solution.

Understanding the underlying reaction mechanisms responsible for aluminosilicate glass dissolution in aqueous environments is crucial for designing glasses for technological applications ranging from architecture windows and touch screens to nuclear waste disposal. This study investigated the glass composition effect on the interfacial reactions of sodium aluminosilicate (NAS) glasses using molecular dynamics (MD) simulations with recently developed reactive potentials. Glass-water interfacial models of six NAS glasses with varying AlO/NaO ratios were investigated for up to 4 nanoseconds (ns) to elucidate the interfacial reaction mechanisms at ambient temperature.

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.

Molecular mechanisms causing anomalously high thermal expansion of nanoconfined water.

Anomalously high thermal expansion is measured in water confined in nanoscale pores in amorphous silica and the molecular mechanisms are identified by molecular dynamics (MD) simulations using an accurate dissociative water potential. The experimentally measured coefficient of thermal expansion (CTE) of nanoconfined water increases as pore dimension decreases. The simulations match this behavior for water confined in 30 A and 70 A pores in silica.