Polar mixtures under nanoconfinement
We present results from molecular dynamics simulations describing structural and dynamical characteristics of equimolar mixtures of water and acetonitrile, confined between two silica walls separated at interplate distances of d = 0.6, 1, and 1.5 nm. Two different environments were investigated: a f...
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2009
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v113_n38_p12744_Rodriguez http://hdl.handle.net/20.500.12110/paper_15206106_v113_n38_p12744_Rodriguez |
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paper:paper_15206106_v113_n38_p12744_Rodriguez2023-06-08T16:19:01Z Polar mixtures under nanoconfinement Rodriguez, Javier Elola, María Dolores Laria, Daniel Hector Acetonitrile Hydrogen Hydrogen bonds Hydrophilicity Mixtures Molecular dynamics Organic solvents Silica Walls (structural partitions) Acetonitrile molecules Aqueous layer Bound waters Bulk mixtures Concentration of Confined water Dynamical characteristics Equimolar mixtures Hydrogen bondings Hydrophilic environments Hydrophilic plates Hydrophobic confinement Liquid slabs Molecular dynamics simulations Nanoconfinements Rotational motion Silanol groups Silica substrate Silica surface Solvation layers Solvent dispersions Solvent mixtures Water molecule Molecules We present results from molecular dynamics simulations describing structural and dynamical characteristics of equimolar mixtures of water and acetonitrile, confined between two silica walls separated at interplate distances of d = 0.6, 1, and 1.5 nm. Two different environments were investigated: a first one where wall-solvent dispersion forces prevail (hydrophobic confinement) and a second one in which the terminal O atoms at the silica surface are transformed into silanol groups (hydrophilic confinement). For the former case, we found that, at the shortest interplate distance examined, the confined region is devoid of water molecules. At an interplate distance of the order of 1 nm, water moves into the confined region, although, in all cases, there is a clear enhancement of the local concentration of acetonitrile in detriment of that of water. Within hydrophilic environments, we found clear distinctions between a layer of bound water lying in close contact with the silica substrates and a minority of confined water that occupies the inner liquid slab. The bound aqueous layer is fully coordinated to the silanol groups and exhibits minimal hydrogen bonding with the second solvation layer, which exclusively includes acetonitrile molecules. Dynamical characteristics of the solvent mixture are analyzed in terms of diffusive and rotational motions in both environments. Compared to bulk mixtures, we found significant retardations in all dynamical modes, with those ascribed to water molecules bound to the hydrophilic plates being the most dramatic. © 2009 American Chemical Society. Fil:Rodriguez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Elola, M.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Laria, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v113_n38_p12744_Rodriguez http://hdl.handle.net/20.500.12110/paper_15206106_v113_n38_p12744_Rodriguez |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Acetonitrile Hydrogen Hydrogen bonds Hydrophilicity Mixtures Molecular dynamics Organic solvents Silica Walls (structural partitions) Acetonitrile molecules Aqueous layer Bound waters Bulk mixtures Concentration of Confined water Dynamical characteristics Equimolar mixtures Hydrogen bondings Hydrophilic environments Hydrophilic plates Hydrophobic confinement Liquid slabs Molecular dynamics simulations Nanoconfinements Rotational motion Silanol groups Silica substrate Silica surface Solvation layers Solvent dispersions Solvent mixtures Water molecule Molecules |
| spellingShingle |
Acetonitrile Hydrogen Hydrogen bonds Hydrophilicity Mixtures Molecular dynamics Organic solvents Silica Walls (structural partitions) Acetonitrile molecules Aqueous layer Bound waters Bulk mixtures Concentration of Confined water Dynamical characteristics Equimolar mixtures Hydrogen bondings Hydrophilic environments Hydrophilic plates Hydrophobic confinement Liquid slabs Molecular dynamics simulations Nanoconfinements Rotational motion Silanol groups Silica substrate Silica surface Solvation layers Solvent dispersions Solvent mixtures Water molecule Molecules Rodriguez, Javier Elola, María Dolores Laria, Daniel Hector Polar mixtures under nanoconfinement |
| topic_facet |
Acetonitrile Hydrogen Hydrogen bonds Hydrophilicity Mixtures Molecular dynamics Organic solvents Silica Walls (structural partitions) Acetonitrile molecules Aqueous layer Bound waters Bulk mixtures Concentration of Confined water Dynamical characteristics Equimolar mixtures Hydrogen bondings Hydrophilic environments Hydrophilic plates Hydrophobic confinement Liquid slabs Molecular dynamics simulations Nanoconfinements Rotational motion Silanol groups Silica substrate Silica surface Solvation layers Solvent dispersions Solvent mixtures Water molecule Molecules |
| description |
We present results from molecular dynamics simulations describing structural and dynamical characteristics of equimolar mixtures of water and acetonitrile, confined between two silica walls separated at interplate distances of d = 0.6, 1, and 1.5 nm. Two different environments were investigated: a first one where wall-solvent dispersion forces prevail (hydrophobic confinement) and a second one in which the terminal O atoms at the silica surface are transformed into silanol groups (hydrophilic confinement). For the former case, we found that, at the shortest interplate distance examined, the confined region is devoid of water molecules. At an interplate distance of the order of 1 nm, water moves into the confined region, although, in all cases, there is a clear enhancement of the local concentration of acetonitrile in detriment of that of water. Within hydrophilic environments, we found clear distinctions between a layer of bound water lying in close contact with the silica substrates and a minority of confined water that occupies the inner liquid slab. The bound aqueous layer is fully coordinated to the silanol groups and exhibits minimal hydrogen bonding with the second solvation layer, which exclusively includes acetonitrile molecules. Dynamical characteristics of the solvent mixture are analyzed in terms of diffusive and rotational motions in both environments. Compared to bulk mixtures, we found significant retardations in all dynamical modes, with those ascribed to water molecules bound to the hydrophilic plates being the most dramatic. © 2009 American Chemical Society. |
| author |
Rodriguez, Javier Elola, María Dolores Laria, Daniel Hector |
| author_facet |
Rodriguez, Javier Elola, María Dolores Laria, Daniel Hector |
| author_sort |
Rodriguez, Javier |
| title |
Polar mixtures under nanoconfinement |
| title_short |
Polar mixtures under nanoconfinement |
| title_full |
Polar mixtures under nanoconfinement |
| title_fullStr |
Polar mixtures under nanoconfinement |
| title_full_unstemmed |
Polar mixtures under nanoconfinement |
| title_sort |
polar mixtures under nanoconfinement |
| publishDate |
2009 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v113_n38_p12744_Rodriguez http://hdl.handle.net/20.500.12110/paper_15206106_v113_n38_p12744_Rodriguez |
| work_keys_str_mv |
AT rodriguezjavier polarmixturesundernanoconfinement AT elolamariadolores polarmixturesundernanoconfinement AT lariadanielhector polarmixturesundernanoconfinement |
| _version_ |
1768542002269388800 |