Multilayer adsorption of ethylene on graphite: Layering, prewetting, and wetting
We report the results of a comprehensive x-ray-scattering study of multilayer ethylene physisorbed on graphite. At temperatures well below the triple point of bulk ethylene (103.8 K), adsorption only occurs up to a finite number of layers; any further addition of material results in the nucleation of bulk crystallites. The number of layers that coexist with bulk increases at successively increasing transition temperatures. Reversible, first-order transitions between the total number of layers adsorbed and the coexisting bulk are observed at T = 75 K (one to two layers) and at T = 98 K (two to three layers). Bulk particle-size information is obtained as a function of both temperature and the amount of material in the cell. We present evidence that suggests that ethylene undergoes a thin-film to thick-film transition immediately below the triple point and that the triple point is the wetting temperature of ethylene on graphite. Pronounced hysteresis effects are observed both at the layering transitions and in the neighborhood of the triple point.
- Research Organization:
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- OSTI ID:
- 6494078
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 30:1; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603* -- Materials-- Properties
ADSORPTION
ALKENES
CARBON
COHERENT SCATTERING
DATA
DIFFRACTION
ELEMENTAL MINERALS
ELEMENTS
ETHYLENE
EXPERIMENTAL DATA
FILMS
GRAPHITE
HYDROCARBONS
HYSTERESIS
INFORMATION
LAYERS
LOW TEMPERATURE
MINERALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHASE TRANSFORMATIONS
SCATTERING
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMODYNAMICS
WETTABILITY
X-RAY DIFFRACTION