MODELING THE CLAY WATER INTERFACE

To model the clay-water interactions, we use a molecular description of the solvent and clay sheet. The clay-water and clay-cation potentials are obtained from quantum calculations. These potentials are used in Monte Carlo simulations of the solvation of two montmorillonite sheets and their interlamellar sodium counterions. We obtain an immersion enthalpy and mean water orientation in agreement with the experimental data. The results show the importance of the solvation of the interlamellar cations on the swelling properties of the clay.