Atomic-force and fluorescence microscopy of Langmuir-Blodgett monolayers of [ital L]-[alpha]-dimyristoylphosphatidic acid

Journal Article · Mon Nov 15 04:00:00 EST 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.14479· OSTI ID:5840492

Mikrut, J M ^[1]; Dutta, P; Ketterson, J B ^[2]; MacDonald, R C ^[1]

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1. Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208 (United States)
2. Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States)

We have obtained fluorescence and atomic-force-microscopy images of the liquid and solid phases of Langmuir-Blodgett monolayers of [ital L]-[alpha]-dimyristoylphosphatidic acid, some containing [similar to]1 mol % of [ital L]-[alpha]-phosphatidylethanolamine-[ital N]-4-nitrobenzo-2-oxa-1,3-diazole. The fluorescence microscopy images are similar to those of monolayers at the air-water interface, but slight differences indicate that changes occur in the monolayers as a result of the deposition process. The atomic-force-microscopy images show the clean glass substrates to be very much rougher than when the monolayers are deposited on them. We propose that a water layer provides a smooth surface on which the Langmuir-Blodgett monolayers rest. We measured a [similar to]25-A height difference between the liquid and solid phase region, one explanation being that the alkyl chains of the molecule are standing up in the solid phase and lying down in the liquid phase. This result is consistent with the fluorescence and atomic-force-microscopy images which show an increase in the amount of solid phase domains as a result of the deposition process. Further, the atomic-force-microscopy images of the monolayers show features which have not been described before and which could not be attributed to the presence of the dye. Finally, we showed that if the Langmuir-Blodgett monolayers are not stored in a humid environment, they begin to collapse into multilayers.

• DOE Contract Number: FG02-84ER45125
• OSTI ID: 5840492
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:19; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
AIR
DEPOSITION
ESTERS
FILMS
FLUIDS
FLUORESCENCE
GASES
GLASS
HYDROGEN COMPOUNDS
INTERFACES
LIPIDS
LIQUIDS
LUMINESCENCE
MICROSCOPY
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHOLIPIDS
ROUGHNESS
SOLIDS
SURFACE PROPERTIES
THIN FILMS
WATER