X-ray-diffraction study of the superliquid region of the phase diagram of a Langmuir monolayer

Journal Article · Wed Apr 15 04:00:00 EDT 1992 · Physical Review A. General Physics; (United States)

DOI:https://doi.org/10.1103/PhysRevA.45.5734· OSTI ID:7047894

Shih, M C; Bohanon, T M; Mikrut, J M ^[1]; Zschack, P ^[2]; Dutta, P ^[1]

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1. Department of Physics Astronomy, Northwestern University, Evanston, Illinois 60208 (United States)
2. Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

Lipid-monolayer isotherms often show a kink that changes to a flat section and back to a kink within a narrow temperature range. In heneicosanoic acid monolayers, along a high-pressure isobar, we have observed a slightly distorted rotator-I'' phase between the known distorted hexagonal and hexagonal phases. Isotherms show a flat section only where this new phase occurs. The diffraction peaks are broader in this phase than in the adjacent phases; this reentrant behavior occurs in the same region of the phase diagram where the viscosity shows anomalous trends (first reported, we believe, by Copeland, Harkins, and Boyd (J. Chem. Phys. 10, 357 (1942)) and thought to indicate a superliquid'' phase).

• DOE Contract Number: FG02-84ER45125
• OSTI ID: 7047894
• Journal Information: Physical Review A. General Physics; (United States), Journal Name: Physical Review A. General Physics; (United States) Vol. 45:8; ISSN 1050-2947; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
COHERENT SCATTERING
DIAGRAMS
DIFFRACTION
FILMS
ISOTHERMS
LIPIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHASE DIAGRAMS
PHASE STUDIES
SCATTERING
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION