Surface behavior of N-dodecylimidazole at air/water interfaces
Using molecular dynamics techniques, we investigate surface states of the surfactant N-dodecylimidazole (DIm) in its basic and acid forms adsorbed at the water/air interface. Two different surface coverages were examined: an infinitely diluted detergent and a saturated monolayer. Spatial and orienta...
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| Autores principales: | , |
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2007
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19327447_v111_n2_p908_Rodriguez http://hdl.handle.net/20.500.12110/paper_19327447_v111_n2_p908_Rodriguez |
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| Sumario: | Using molecular dynamics techniques, we investigate surface states of the surfactant N-dodecylimidazole (DIm) in its basic and acid forms adsorbed at the water/air interface. Two different surface coverages were examined: an infinitely diluted detergent and a saturated monolayer. Spatial and orientational correlations of the surfactants and the aqueous substrate are presented. At large surface coverages, Dim presents two solvation states with well differentiated structural and dynamical characteristics. Solvation of the protonated surfactant becomes unstable at large concentrations, while the relative stability of the surface states of N-dodecylimidazolium (DImH +) with respect to bulk states increases at infinite dilution. The surface acidic behavior of DImH+ was investigated using a multistate empirical valence bond Hamiltonian model. Our simulation results suggest that the acidic characteristics of Dim are enhanced at the surface. The differences are rationalized in terms of the distinctive features in the overall solvation structure of the reactive complex. © 2007 American Chemical Society. |
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