| Titre : | Multilayer adsorption of gases on graphite studied by ellipsometry |
| Auteurs : | Mahrez Drir, Auteur ; George B. Hess, Directeur de thèse |
| Type de document : | texte imprimé |
| Editeur : | University of Virginia, 1986 |
| Format : | 156 f. / ill. / 27 cm. |
| Note générale : |
Thèse de Doctorat : Physique : Virginia, University of Virginia : 1986
Bibliogr. f. 157 - 165 |
| Langues : | Anglais |
| Index. décimale : | D002486 |
| Tags : | Adsorption -- gases Single cleaved surface Highly oriented pyrolitic graphite Ellipsometric technique |
| Résumé : |
In this work we report adsorption measurements on a single cleaved surface of highly oriented pyrolitic graphite (HOPG).
This eliminates the possibility of capillary condensation, while providing a surface with larger facet size and better energy uniformity than exfoliated graphite. We have measured adsorbate coverage by a phase-modulation ellipsometric technique, using laser light reflected from a 0.1 x 0.2 mm spot on the graphite surface. We have studied various gases (Kr, O₂, C₂H₄ and CF₄) in the vicinity of their respective bulk triple point Tt (except for the case of Kr where all the data were recorded below Tt). We have observed layer-by-layer adsorption where as many as nine steps could be seen. The overall features were characteristic of wetting at the triple point: below Tt, bulk crystallite formation preempts film growth after a limited number of layers. Above Tt, the film grows to a thickness equivalent to about 40-50 layers. However, indications of bulk droplets appear above about 10-12 layers. Our results suggest not quite complete wetting by the liquid phase of the various gases studied. |
Exemplaires (1)
| Cote | Support | Localisation | Section | Disponibilité | Spécialité | Etat_Exemplaire |
|---|---|---|---|---|---|---|
| D002486 | Papier + ressource électronique | Bibliothèque Annexe | Thèse de Doctorat | Disponible | Autre | Consultation sur place/Téléchargeable |
Documents numériques (1)
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DRIR.Mahrez.pdf URL
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