Monomolecular film behavior of a homologous series of 1,2-bis(.omega.-cyclohexylacyl)phosphatidylcholines at the air/water interface

Langmuir ◽  
1989 ◽  
Vol 5 (1) ◽  
pp. 30-34 ◽  
Author(s):  
B. Asgharian ◽  
D. K. Rice ◽  
D. A. Cadenhead ◽  
R. N. A. H. Lewis ◽  
R. N. McElhaney
Keyword(s):  
Homologous Series ◽  
Water Interface ◽  
Monomolecular Film ◽  
Air Water Interface

Metastability in Monolayer Films Transferred onto Solid Substrates by the Langmuir-Blodgett Method: IR Evidence for Transfer-Induced Phase Transitions

1994 ◽  
Vol 48 (10) ◽  
pp. 1196-1203 ◽  
Author(s):  
Fazale R. Rana ◽  
Suci Widayati ◽  
Brian W. Gregory ◽  
Richard A. Dluhy
Keyword(s):  
Fatty Acid ◽  
Conformational Changes ◽  
Structural Changes ◽  
High Surface ◽  
Solid Substrate ◽  
Water Interface ◽  
Monolayer Films ◽  
Langmuir Blodgett ◽  
Monomolecular Film ◽  
Air Water Interface

The rate at which a monomolecular film is deposited onto a solid substrate in the Langmuir-Blodgett process of preparing supported monolayer films influences the final structure of the transferred film. Attenuated total reflectance infrared spectroscopic studies of monolayers transferred to germanium substrates show that the speed at which the substrate is drawn through the air/water interface influences the final conformation in the hydrocarbon chains of amphiphilic film molecules. This transfer-induced effect is especially evident when the monolayer is transferred from the expanded region of surface-pressure-molecular-area isotherms at low surface pressures; the effect is minimized when the film molecules are transferred from condensed phases at high surface pressures. This phenomenon has been observed for both a fatty acid and a phospholipid, which suggests that these conformational changes may occur in a variety of hydrocarbon amphiphiles transferred from the air/water interface. This conformational ordering may be due to a kinetically limited phase transition taking place in the meniscus formed between the solid substrate and aqueous subphase. In addition, the results obtained for both the phospholipid and fatty acid suggest that the structure of the amphiphile may help determine the extent and nature of the transfer-speed-induced structural changes taking place in the monomolecular film.

Monomolecular film behavior of tetraether lipids from a thermoacidophilic archaebacterium at the air/water interface

Langmuir ◽  
1990 ◽  
Vol 6 (5) ◽  
pp. 1017-1023 ◽  
Author(s):  
J. L. Dote ◽  
W. R. Barger ◽  
F. Behroozi ◽  
E. L. Chang ◽  
S. L. Lo ◽  
...  
Keyword(s):  
Water Interface ◽  
Monomolecular Film ◽  
Air Water Interface ◽  
Tetraether Lipids

Interactions Between Ferredoxin and Chlorophyll in a Monolayer System

1971 ◽  
Vol 26 (9) ◽  
pp. 922-929 ◽  
Author(s):  
Seymour Steven Brody
Keyword(s):  
Surface Tension ◽  
Quantum Yield ◽  
Chlorophyll A ◽  
Surface Potential ◽  
Nitrogen Atmosphere ◽  
Water Interface ◽  
Monomolecular Film ◽  
Air Water Interface ◽  
Surface Active

Ferredoxin (Fd) is surface active; both its area/molecule, A, and surface potential, ΔV, (at an air-water interface) vary with the pH of the subphase. From the surface isotherms (at pH 7.7) A and ΔV are 167 A2 and 170 ± 20 mV, respectively, when the surface tension is 10 dyne/cm.Fd and chlorophyll a (Chl) appear to form a mixed monomolecular film. At pH 7.7 a maximum interaction between Fd and Chl is observed when the monolayer contains a mole ratio of Fd/Chl ≅ 2. Irradiaion of Chl-Fd films, in nitrogen atmosphere, results in a bleaching of Chl and an increase of ΔV. The quantum yield for this bleaching is estimated to be 0.4.

Syntheses of Azobenzene Derivatives Having Fluoroalkyl Chain and Their Monomolecular Film Formation at the Air/Water Interface

1992 ◽  
Vol 65 (8) ◽  
pp. 2141-2144 ◽  
Author(s):  
Norio Yoshino ◽  
Mitsuharu Kitamura ◽  
Tsuyoshi Seto ◽  
Yasuhiro Shibata ◽  
Masahiko Abe ◽  
...  
Keyword(s):  
Film Formation ◽  
Water Interface ◽  
Monomolecular Film ◽  
Air Water Interface ◽  
Azobenzene Derivatives

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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