Surface and Magnetic Orientation in a Type II Nematic Lyomesophase

Amáral, L. Q.; Rossi, Wagner Costa

doi:10.1080/00268948308071056

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…I focused on the planar geometry with results in the Nd phase—passing the Nc phase (with potassium laurate) to the Ph.D. student—and the work on interactions between micelles, considering Van der Waals attraction, Coulomb repulsion, and excluded volume gave interesting results [ 35 ]. A following master’s degree studied the interaction between surface and magnetic orientation [ 36 ].…”

Section: Self-assembly and Lyotropic Liquid Crystalsmentioning

confidence: 99%

Supramolecular Aggregates: Hardness Plus Softness

Amáral

2021

Molecules

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The properties of supramolecular aggregates cross several disciplines, embracing the sciences of nature and joining theory, experiment, and application. There are few articles centering on the problems of interdisciplinarity, and this paper gives an alternative approach, starting with scientific divulgation, bringing concepts from their origin, to facilitate the access of young scientists to the scientific content. Didactic examples are taken from the experience of the author in changing directions of research due to several circumstances of life (including maternity), starting from the view of a rigorous student of physics and evolving to several subjects in chemistry. The scientific part starts with concepts related to nuclear interactions, using the technique of neutron scattering in reactors, and evolves to research in molecular physics. Finally, it arrives at the academic context, with research in condensed matter physics, with X-ray and other techniques, starting with detergents forming nematic lyotropic liquid crystals and the phase transition sequence of isotropic to nematics to hexagonal. The scientific subjects evolved to biological and bio-inspired liquid crystals, including DNA and also specific lipids and phospholipids in biomimetic membranes. Special attention is given to the question of distribution of matter in these complex systems and the non-trivial connections between biochemistry, structures, auto-aggregation, and biology.

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Section: Self-assembly and Lyotropic Liquid Crystalsmentioning

confidence: 99%

Supramolecular Aggregates: Hardness Plus Softness

Amáral

2021

Molecules

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“…In the plane AB there is an escape of the director in the direction of the capillary axis. This plane, which is clearly visible to the naked eye in thick capillaries (Amaral & Rossi, 1983) and by OM observation of usual capillaries (Santos Bittencourt & Amaral, 1989), is not sensed by XD, since it represents a small fraction of the bulk sample.…”

Section: ( B ) Magnetic Orientationmentioning

confidence: 99%

“…Although the observed surface orientation implies a strong anchoring, it should be remarked that such anchoring occurs without the necessity of special surface treatment procedures. Previous measurements in capillaries with a conic form and variable thickness (Amaral & Rossi, 1983) yielded evidence that strong surface orientation occurs for capillary diameters up to 1.5-1.9 mm. For larger diameters the optical texture becomes typical of disoriented samples.…”

Section: T X-ray Beammentioning

confidence: 99%

“…The resulting director field (Amaral & Rossi, 1983;Santos Bittencourt & Amaral, 1989) is shown in Fig. 3(b).…”

Section: ( B ) Magnetic Orientationmentioning

confidence: 99%

“…The results for Nc are rather trivial: the intensity rises as a function of sample thickness. The results for Nd may be understood in terms of the director field expected for a cylindrical capillary with homeotropic surface alignment (Cladis & Kleman, 1972;Williams, Pieranski & Cladis, 1972;Meyer, 1973;Williams & Bouligand, 1974;Amaral & Rossi, 1983;Santos Bittencourt & Amaral, 1989), as displayed in Fig. 3(a).…”

Section: (A) Surface Orientation (Geometry Go-no Magnetic Field Applied)mentioning

confidence: 99%

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Characterization of nematic lyomesophases by X-ray diffraction

Amáral¹

1989

J Appl Cryst

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Procedures for an independent characterization of lyotropic nematics by X-ray diffraction (XD) are presented. Nc (cylindrical micelles) and Nd (discotic micelles) can be distinguished on the basis of surface orientation alone by a method of sample scanning through the X-ray beam. The sign of the diamagnetic anisotropy susceptibility can also be independently obtained. The differences between optical and XD information for such a characterization are discussed.

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Chemical microscopy

Cooke¹

1986

Anal. Chem.

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This is a review of the publications in chemical microscopy from January 1984 through December 1985, primarily as documented in Chemical Abstracts. The review stresses advances in microscopical techniques, primarily using the polarized light microscope, and in instrumentation related to present or potential analytical methods.As in previous reviews, certain topics are excluded; for example, virtually all publications concerning transmission electron microscopy or scanning electron microscopy are omitted, as are publications of a more theoretical nature.The alphanumeric referencing scheme and major text divisions are the same as in recent reviews, for the readers' convenience: sections range from A1 through Zl, A2 through Z2, etc., and citations are referenced within a section by the rightmost one or two digits as in A1.9 or R2.6. References cited here were obtained from a computer search of Chemical Abstracts and a manual search of regularly abstracted, major science, biology and microbiology, geology, chemistry, asbestos analysis, art conservation, and pure and applied research are but a few. New and improved instrumentation and techniques for sampling, preparing, and viewing specimens for examination have been pursued along with advances in photomacroand photomicrographic methods, and will be of interest to the amateur as well as professional microscopists. Worth men-

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Surface and Magnetic Orientation in a Type II Nematic Lyomesophase

Cited by 6 publications

References 9 publications

Supramolecular Aggregates: Hardness Plus Softness

Supramolecular Aggregates: Hardness Plus Softness

Characterization of nematic lyomesophases by X-ray diffraction

Chemical microscopy

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