Tilt stripe textures in Langmuir monolayers of fatty acids

Schwartz, Daniel K.; Ruíz-García, Jaime; Qiu, Xia; Selinger, Jonathan V.; Knobler, Charles M.

doi:10.1016/0378-4371(94)90449-9

Cited by 28 publications

(12 citation statements)

References 20 publications

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“…In several of the acid/ester mixtures we found that long, wide stripes, Fig. 6͑a͒, reminiscent of those found in several acids 19,20 formed in the L 2 and Ov phases after repeated cycling of the monolayer into the LS phase. The edges of the stripes are smooth in the L 2 phase but they immediately develop a zig-zag form when the L 2 /Ov boundary is crossed, Fig.…”

Section: Figures 2 Andsupporting

confidence: 59%

“…The zig-zag relaxes rapidly as the pressure is dropped and the phase boundary is recrossed. Schwartz et al 20 had observed a similar zig-zag transition in stripes of pentadecanoic acid but did not understand its origins. If one adjusts the temperature for the difference in chain length it is apparent that the transition in pentadecanoic acid also occurred at the L 2 /Ov boundary.…”

Section: Figures 2 Andmentioning

confidence: 99%

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Optical measurements of the phase diagrams of Langmuir monolayers of fatty acid, ester, and alcohol mixtures by Brewster-angle microscopy

Teer

Knobler

Lautz

et al. 1997

The Journal of Chemical Physics

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Surface pressure-temperature phase diagrams have been determined by Brewster-angle microscopy for Langmuir monolayers of heneicosanoic acid with the esters methyl and ethyl heneicosanoate and octadecanoic acid with methyl, ethyl, and propyl octadecanoate. The behavior is similar to that found previously in mixtures of an acid and an alcohol. In each case with increasing ester concentration the L 2 /L 2 Ј phase boundary moves toward lower pressure and higher temperature while the L 2 /Ov boundary moves toward lower pressure and lower temperature. The L 2 Ј and Ov phases eventually merge and the boundary with the L 2 phase moves to zero pressure. The phase diagram of eicosyl acetate is similar to that of the fatty acids. We attribute the variations in the diagrams to the extent of hydrogen bonding between the head group and the subphase.

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Section: Figures 2 Andsupporting

confidence: 59%

Section: Figures 2 Andmentioning

confidence: 99%

Optical measurements of the phase diagrams of Langmuir monolayers of fatty acid, ester, and alcohol mixtures by Brewster-angle microscopy

Teer

Knobler

Lautz

et al. 1997

The Journal of Chemical Physics

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“…Microscopic observation of the textures of Langmuir monolayers became possible one and a half decades ago, first by fluorescence microscopy − and more recently by ellipsometric microscopy − and Brewster angle microscopy (BAM). , These methods have been used to clarify the surface phase diagram of long-chain fatty acid monolayers and to identify characteristic domain structures of its various phases , and multilayers , have provided new insights into these processes.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Thickness and Optical Properties of a Langmuir Film from the Domain Morphology by Brewster Angle Microscopy

Mul

Mann

1998

Langmuir

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A method employing Brewster angle microscopy was developed to measure the relative thickness of monolayers and multilayers at the air−water interface. Results proved that multilayers in ultrathin films of 8CB (4‘-n-alkyl[1,1‘-biphenyl]-4-carbonitrile; nCB, n = 8) are built up from one or two stacked bilayers on top of a monolayer at the air−water interface covered by a continuous bilayer. In addition, the fan texture of the mixed splay-bend disclination defects, which are formed in 10CB monolayers on reverse collapse of a continuous trilayer, was used to obtain estimates for the components of the anisotropic dielectric constant of the monomolecular film. This estimate was made by comparing experimental images with computationally generated model images based on an assumed director distribution around the defect. The results support the validity of the folding mechanism of multilayer generation and reverse collapse as opposed to the condensation mechanism. Finally, comparison of the experimental and theoretical values of the ratio of the multilayer thickness and the monolayer thickness indicates that at this level the water−film interface cannot be assumed to be sharp or well defined.

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“…1. The stripes are 50-100 ~m in width; they widen with increasing pressure at constant temperature and narrow with increasing temperature at constant pressure [10,11]. [9].)…”

Section: -Resultsmentioning

confidence: 99%

Ordering in two dimensions: Optical textures in monolayers

Knobler¹

1994

Nouv Cim D

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Optical studies of Langmuir monolayers of simple amphiphiles such as fatty acids and esters by polarized fluorescence microscopy and Brewster-angle microscopy reveal a large variety of textures including stripes, stars, and spirals that closely resemble textures observed in liquid crystals. The textures represent large-scale ( > 10 ~) spontaneous organization of the molecular tilt azimuth. Phase transitions within the monolayer can be directly observed by marked changes in texture, revealing a complex phase diagram. Many of the textures can be explained by a Landau-deGennes theory of tilted hexatic phases that takes into account the broken-symmetry characteristic of amphiphiles at an interface. PACS 68.10 -Fluid surfaces and fluid-fluid interfaces. PACS 64.70.Md -Transitions in liquid crystals. PACS 61.30.Jf-Defects in liquid crystals. PACS 68.15 -Liquid thin films. PACS 01.30.Cc -Conference proceedings.

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Tilt stripe textures in Langmuir monolayers of fatty acids

Cited by 28 publications

References 20 publications

Optical measurements of the phase diagrams of Langmuir monolayers of fatty acid, ester, and alcohol mixtures by Brewster-angle microscopy

Optical measurements of the phase diagrams of Langmuir monolayers of fatty acid, ester, and alcohol mixtures by Brewster-angle microscopy

Determination of the Thickness and Optical Properties of a Langmuir Film from the Domain Morphology by Brewster Angle Microscopy

Ordering in two dimensions: Optical textures in monolayers

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