Investigation into Interlayer Water Structure in Na+- and Ca2+-Montmorillonite: A Molecular Dynamics Study

Swelling clays play significant roles in current industry. Molecular dynamics simulations have been performed to investigate the swelling properties, hydration behaviour and mobility of interlayer molecules of Na+- and Ca2+-montmorillonites. More specifically, to characterize the structure and energetics of Na+ and Ca2+ adsorption as functions of water content; the relationships between the coordination environments of clay surface-interlayer water-exchangeable cations; the influence of cation hydration energy on the dynamics and swelling mechanism of clays; and the influence of charge distribution on all of the above. Establishing an understanding of these clay/water systems is viewed as a sensible foundation for the more complex systems.