Diffusion processes in confined materials.
Magn Reson Imaging
; 16(5-6): 579-81, 1998.
Article
en En
| MEDLINE
| ID: mdl-9803913
The diffusion coefficient for cyclohexane confined within pores of diameter 40 to 500 A has been measured as a function of temperature between 296 and 180 K, and is compared to values obtained for the bulk material. A substantial liquid-like signal is observed in the region of the depressed freezing points and a diffusion coefficient is measurable in all samples to well below these temperatures. The diffusion data appear to be continuous over the freezing region. These observations suggest persisting molten layers at interfaces which exchange with crystals forming within the silica pores. The diffusion coefficient of the molecules in the surface layer is three orders of magnitude larger than in the plastic phase of bulk cyclohexane.
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Banco de datos:
MEDLINE
Asunto principal:
Espectroscopía de Resonancia Magnética
/
Dióxido de Silicio
/
Ciclohexanos
Límite:
Humans
Idioma:
En
Revista:
Magn Reson Imaging
Año:
1998
Tipo del documento:
Article
País de afiliación:
Noruega