Lattice structures and molecular tilts in Langmuir monolayers of saturated fatty acid--alcohol mixtures

Journal Article · Tue Nov 15 04:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.468042· OSTI ID:7126504

Shih, M C; Durbin, M K; Malik, A ^[1]; Zschack, P ^[2]; Dutta, P ^[1]

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

We have studied Langmuir monolayers composed of mixtures of heneicosanoic acid and heneicosanol using [pi]-[ital A] isotherms and x-ray diffraction. We find that the two materials are miscible in monolayer form. We have determined how the phase diagram of the acid evolves to that of the alcohol as the composition varies. X-ray diffraction data along isotherms and isobars show that the head--head interactions, like the tail--tail interactions, are anisotropic. The swiveling transition'' between phases with different tilt directions is accompanied by a rotation of the molecules about their long axes.

• DOE Contract Number: FG02-84ER45125
• OSTI ID: 7126504
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:10; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ALCOHOLS
CARBOXYLIC ACIDS
CHEMICAL COMPOSITION
COHERENT SCATTERING
COUPLING
CRYSTAL STRUCTURE
DIAGRAMS
DIFFRACTION
DISPERSIONS
HYDROXY COMPOUNDS
ISOTHERMS
LAYERS
MIXTURES
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORIENTATION
PHASE DIAGRAMS
SCATTERING
X-RAY DIFFRACTION