Stabilization of Unstable Components in Langmuir–Blodgett Film System by Introduction of Water-Soluble Antioxidants

Iriyama, Keiji; Yoshiura, Masahiko

doi:10.1246/cl.1989.1635

Cited by 3 publications

(3 citation statements)

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“…In fact, the π-A isotherms of cholesterol monolayers reported by the former investigators 8,9 seem to be more expanded at low surface pressures than those reported by Baglioni et al 6 or ours.…”

Section: Resultssupporting

confidence: 43%

“…Both π− A curves for cholesterol and cholestanol monolayers spread on a water surface did not change when the compression was initiated 1 h (longer time than that needed for transfer of one monolayer onto a substrate plate) after spreading. Several investigators , reported a considerable shift of the π−A curves of cholesterol monolayers toward larger areas when compression is initiated ca. 1 h after spreading.…”

Section: Resultsmentioning

confidence: 99%

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Surface Chemical and Morphological Study on Monolayers of Cholesterol, Cholestanol, and Their Derivatives Conjugated with Amino Acid

et al. 1997

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Section: Resultssupporting

confidence: 43%

Section: Resultsmentioning

confidence: 99%

Surface Chemical and Morphological Study on Monolayers of Cholesterol, Cholestanol, and Their Derivatives Conjugated with Amino Acid

et al. 1997

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“…Iriyama , examined the stability of Chl- a in multilayer LB films and suggested preferable conditions for fabricating high-quality LB films of Chl- a . Iriyama and Yoshiura explored morphological properties of LB films of Chl- a by electron microscopy combined with a plasma replica method. The resultant micrographs revealed the existence of irregular structure due to uric acid that they employed as an antioxidant in the LB films.…”

Section: Introductionmentioning

confidence: 99%

Control of Molecular Arrangement in Langmuir−Blodgett Films of Chlorophyll a Prepared in Various Gas Phases Studied by Ultraviolet−Visible and Infrared Spectroscopies and Atomic Force Microscopy^,

Sato¹,

Ozaki²,

Oishi³

et al. 1997

Langmuir

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Attenuated total reflection (ATR)/Fourier-transform infrared (FT-IR) spectra were measured for one-monolayer Langmuir−Blodgett (LB) films of chlorophyll a (Chl-a) fabricated in an argon (Ar) atmosphere. The frequencies of CO stretching bands and marker bands for the coordination number of the central Mg atom suggest that Chl-a takes a five-coordinated dimer in the films prepared in the Ar atmosphere. Ultraviolet−visible (UV−vis) as well as IR spectra were obtained for multilayer LB films of Chl-a prepared in air, Ar, nitrogen (N2), and oxygen (O2) atmospheres. In the cases of the multilayer LB films, spectral features in the CO stretching band region suggest that Chl-a exists as a monomer in the film prepared in air while it assumes a dimer in the films prepared in the Ar, N2, and O2 atmospheres. The marker bands for the coordination number of the Mg atom in the IR spectra indicate that Chl-a is in a five-coordinated state. These results imply that one can control the molecular arrangement in the LB films of Chl-a by changing the atmosphere in which they are prepared. Both the UV−vis and IR spectra of the LB films fabricated in the Ar, N2, and O2 atmospheres are almost identical to each other. This means that O2 does not affect the stability and structure of Chl-a in the monolayer on the aqueous subphase. On the basis of the postulate that CO2, which exists only in air, caused a change in pH of the aqueous subphase, we investigated pH-dependent IR spectral changes for the LB films. The results indicate that the dimer of Chl-a changes into pheophytine a (Phe-a) below pH 6.0 and that the monomer species do not exist through pH 6.0−4.0; therefore, it is unlikely that CO2 changes the pH. Probably CO2 coordinates to the central Mg atom as a fifth ligand in the LB films prepared in air, preventing the keto carbonyl group of another Chl-a molecule from coordinating to it.

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Visualization of two-dimensional crystal growth in a monolayer of stearic acid on the electron microscopic scale

et al. 1991

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Stabilization of Unstable Components in Langmuir–Blodgett Film System by Introduction of Water-Soluble Antioxidants

Cited by 3 publications

References 5 publications

Surface Chemical and Morphological Study on Monolayers of Cholesterol, Cholestanol, and Their Derivatives Conjugated with Amino Acid

Surface Chemical and Morphological Study on Monolayers of Cholesterol, Cholestanol, and Their Derivatives Conjugated with Amino Acid

Control of Molecular Arrangement in Langmuir−Blodgett Films of Chlorophyll a Prepared in Various Gas Phases Studied by Ultraviolet−Visible and Infrared Spectroscopies and Atomic Force Microscopy^,

Visualization of two-dimensional crystal growth in a monolayer of stearic acid on the electron microscopic scale

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Stabilization of Unstable Components in Langmuir–Blodgett Film System by Introduction of Water-Soluble Antioxidants

Cited by 3 publications

References 5 publications

Surface Chemical and Morphological Study on Monolayers of Cholesterol, Cholestanol, and Their Derivatives Conjugated with Amino Acid

Surface Chemical and Morphological Study on Monolayers of Cholesterol, Cholestanol, and Their Derivatives Conjugated with Amino Acid

Control of Molecular Arrangement in Langmuir−Blodgett Films of Chlorophyll a Prepared in Various Gas Phases Studied by Ultraviolet−Visible and Infrared Spectroscopies and Atomic Force Microscopy,

Visualization of two-dimensional crystal growth in a monolayer of stearic acid on the electron microscopic scale

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Control of Molecular Arrangement in Langmuir−Blodgett Films of Chlorophyll a Prepared in Various Gas Phases Studied by Ultraviolet−Visible and Infrared Spectroscopies and Atomic Force Microscopy^,