Interaction of ethanol and water with the {1014} surface of calcite.
Molecular dynamics simulations have been used to model the interaction between ethanol, water, and the {1014} 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 a highly ordered, stable adsorption layer. In contrast, a single water molecule can only form one or other of these interactions and is thus less well bound, resulting in a more 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 in 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 {1014} 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.
Cooke
D J
DJ
Department of Chemical and Biological Sciences, University of Huddersfield, United Kingdom. d.j.cooke@hud.ac.uk
Gray
R J
RJ
Sand
K K
KK
Stipp
S L S
SL
Elliott
J A
JA
D002119:Calcium Carbonate / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D008968:Molecular Conformation; D015203:Reproducibility of Results; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D014867:Water; D000431:Ethanol; D002119:Calcium Carbonate