Adsorption of Octyl Cyanide at the Free Water Surface as Studied by Monte Carlo Simulation
Monte Carlo simulations of the adsorption layer of octyl cyanide have been performed on the canonical (N, V, T) ensemble at 300 K. The systems simulated cover the range of octyl cyanide surface densities from 0.27 to 7.83 μmol/m2. The surface density value at which the saturation of the adsorption l...
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Published in | The journal of physical chemistry. B Vol. 111; no. 21; pp. 5885 - 5895 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
31.05.2007
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Subjects | |
Online Access | Get full text |
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Summary: | Monte Carlo simulations of the adsorption layer of octyl cyanide have been performed on the canonical (N, V, T) ensemble at 300 K. The systems simulated cover the range of octyl cyanide surface densities from 0.27 to 7.83 μmol/m2. The surface density value at which the saturation of the adsorption layer occurs is estimated to be 1.7 μmol/m2. At low surface densities, the main driving force of the adsorption is found to be the formation of hydrogen bonds between the water and octyl cyanide molecules, whereas at higher surface concentrations, the dipole−dipole attraction between the neighboring adsorbed octyl cyanide molecules becomes more important. At low surface concentrations, the water−octyl cyanide hydrogen bonds prefer tilted alignments relative to the interface; however, in the case of the saturated adsorption layer, the number of such hydrogen bonds is maximized, leading to the preference of these bonds for the orientation perpendicular to the interface. Contrary to nonionic surfactants of multiple hydrogen bonding abilities (e.g., 1-octanol, C8E3), the increasing surface concentration of octyl cyanide was not found to lead to considerable competition of the molecules for positions of optimal arrangement. As a consequence, the energy and geometry of the water−octyl cyanide hydrogen bonds are found to be insensitive to the octyl cyanide surface concentration. |
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Bibliography: | ark:/67375/TPS-40H7V4LT-0 istex:B87D7BB1AD9A196300E7D2AD221AEBD7B046E33A ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1520-6106 1520-5207 |
DOI: | 10.1021/jp068566i |