Surface freezing in binary mixtures of chain molecules. II. Dry and hydrated alcohol mixtures.
Phys Rev E Stat Nonlin Soft Matter Phys
; 68(3 Pt 1): 031606, 2003 Sep.
Article
en En
| MEDLINE
| ID: mdl-14524780
Surface freezing is studied in dry and hydrated alcohol mixtures by surface x-ray scattering and surface tension measurements. A crystalline bilayer is formed at the surface a few degrees above the bulk freezing temperature. The packing is hexagonal, with molecules aligned along the surface normal in all cases. The in-plane lattice constant reveals a qualitatively different behavior with composition for hydrated and dry mixtures. The simple theoretical approach used successfully for alkane and deuterated alkane mixtures accounts well also for the alcohol mixtures. The repulsive length-mismatch term opposing the mixing entropy term in the free energy of the mixtures is shown to have a universal behavior for all mixtures studied: protonated alkanes, deuterated alkanes, and dry and wet alcohols. This universality is somewhat counterintuitive in view of the different interactions (e.g., hydrogen bonding in alcohols) in the different mixtures.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Phys Rev E Stat Nonlin Soft Matter Phys
Asunto de la revista:
BIOFISICA
/
FISIOLOGIA
Año:
2003
Tipo del documento:
Article
País de afiliación:
Israel
Pais de publicación:
Estados Unidos