Interaction of Ethanol and Water with the {10(1)over-bar4} Surface of Calcite

Molecular dynamics simulations have been used to model the interaction between ethanol, water, and the {10 (1) over bar4} surface of calcite Our results demonstrate that a single ethanol molecule is able to form two interactions with the mineral surface (both Ca-O and O-H), resulting in 4 highly ordered, stable adsorption layer In contrast, a single water molecule can only form one or other of these inter actions and is thus less well bound, resulting in a mole unstable adsorption layer. Consequently. when competitive adsorption is considered. ethanol dominates the adsorption layer that forms even when the starting configuration consists of a complete monolayer of water at the surface The computational results are m good agreement with the results from atomic force microscopy experiments where it is observed that a layer of ethanol remains attached to the calcite surface, decreasing its ability to interact with water and for growth at the {10 (1) over bar4} surface to occur This observation, and its corresponding molecular explanation, may give some insight into the ability to control crystal form using mixtures of different organic solvents