Structure of sodium silicate water glass—X-ray scattering experiments and force-field molecular dynamics simulations

Sodium silicate water glass is used in various applications as adhesives and lubricants. Herein, we used X-ray scattering experiments and force-field molecular dynamics (MD) simulations to investigate the structure of sodium silicate water glass. The concentrated sodium water glass had a low-Q pre-peak; in contrast, the diluted glass did not, as observed from X-ray scattering experiments. The intensity of the low-Q peak decreased with an increase in pressure. MD simulations provided a structure of sodium silicate water glass with sodium clusters surrounded by hydrated silicate anions at low pressures. These sodium clusters were the origin of the low-Q peaks in the simulated patterns. The sodium clusters dissolved in water with an increase in pressure, and consequently, the intensity of the low-Q peak drastically decreased.