New lyotropic liquid crystals composed of finite nonspherical micelles

Forrest, Bruce J.; Reeves, L. W.

doi:10.1021/cr00041a001

Cited by 225 publications

(117 citation statements)

References 19 publications

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“…is obtained from the 2 3~a i spin-lattice relaxation time (Fig. I), and agrees with that from the other parameters (see Table 1 Simple electrolytes, as well as high surfactant concentrations, are known to induce changes in the size and shape of micelles (2,16,(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49). However, the concentrations associated with the above phenomena, and the exact nature of the changes in the micellar solution, are not well understood.…”

Section: Discussionsupporting

confidence: 81%

The effects of high temperatures (29–123 °C) on critical micelle concentrations in solutions of potassium n-octanoate in deuterium oxide: A nuclear magnetic resonance study

Desando¹,

Reeves²

1986

Can. J. Chem.

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M. A. DESANDO and L. W. REEVES. Can. J . Chem. 64, 1823Chem. 64, (1986. Critical micelle concentrations have been determined for potassium n-octanoate in deuterium oxide over a wide temperature range, 29-123"C, from the concentration dependence of proton nmr spectral parameters (peak positions, and vicinal splitting values of the a-CH2 multiplet) and carbon-13 nrnr chemical shifts. The c.m.c. varies from ca. 0.30 m at ca. 30°C to ca. 0.50 m at ca. 120°C and is at a minimum (0.30-0.35 m) in the temperature range ca. 30-50°C. 2 3~a + spin-lattice relaxation times reveal that a co-counterion (Na') different from that of the surfactant counterion (K') reflects the micellization process. A second critical micelle concentration has been observed around 1.0 m at ca. 30°C. dans l'intervalle de tempkrature de 30 2 50°C. Lcs temps de relaxation spin-rCseau du 2 3~a -rkvelent que la pyCsence d'un contre-ion (Na') diffkrent de celui prCsent dans les surfactants (K-) se rkflete dans le processus de micellisation. A 30°C, on a aussi observC une deuxieme concentration micellaire critique autour de 1.0 rn.[Traduit par la revue]

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Section: Discussionsupporting

confidence: 81%

The effects of high temperatures (29–123 °C) on critical micelle concentrations in solutions of potassium n-octanoate in deuterium oxide: A nuclear magnetic resonance study

Desando¹,

Reeves²

1986

Can. J. Chem.

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“…The orientation.of the director axis for each anomer is most relevant when compared to the direction of the ordering axis for micelles in the liquid crystals themselves. The direction of the ordering axis for an axially symmetric system relative to the magnetic field can be readily deduced by watching the time course of change in the liquid crystal spectrum as it goes from random orientation to fully ordered (12). For potassium laurate, the ordering axis is parallel to the magnetic field.…”

Section: Figurementioning

confidence: 99%

“…Mannose is studied in a liquid crystal formed by ordering potassium laurate micelles in a magnetic field (12). An ability to determine a preferred orientation relative to a liquid crystal axis, or a micelle surface, can be demonstrated.…”

mentioning

confidence: 99%

Deuterium NMR as a structural probe for micelle-associated carbohydrates: D-mannose.

Prestegard¹,

Miner²,

Tyrell³

1983

Proc. Natl. Acad. Sci. U.S.A.

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Residual quadrupole splittings for deuterons on perdeuterated a-and (3-D-mannose oriented in a potassium laurate liquid crystal have been measured. Multiple quantum two-dimensional NMR spectroscopy at high magnetic field is used to gain sufficient resolution to assign splittings to specific sites within these molecules. The assigned splittings are interpreted in terms of molecular geometries and preferred orientations of the molecules relative to the surface of the potassium laurate micelles that make up the liquid crystalline phase.The three-dimensional structures of complex carbohydrates and constituent sugars have become a topic of considerable interest over the last several years. It is now recognized that these molecules play central roles in cellular biology as structural components, as protective layers, as cell surface receptors, and as antigenic determinants (1, 2). Yet these molecules are among the least well characterized of biological macromolecules. Recent advances in high-resolution NMR, mass spectrometry, and diffraction studies (2-6) are providing new primary and secondary structural features, but progress toward an understanding of long-range folding in solution or the nature of membrane surface interactions is slow. Improved analytical methods capable of providing such information would be extremely valuable.Deuterium NMR has shown substantial promise as a probe of structural properties of both large and small molecules. This derives from the fact that this spin one nucleus displays both magnetic field-nuclear magnetic moment interactions and electric field gradient-nuclear quadrupole moment interactions. The former are defined in the laboratory frame by the application of a magnetic field. The latter are defined in the molecular frame by the distribution of electrons in chemical bonds, for example, a deuterium-carbon bond. In ordered systems, the manner in which the two interactions combine depends on the orientation of the bond relative to a molecular frame and on an order parameter matrix describing ordering of the molecule relative to the magnetic field. The interactions lead to two observable transitions for each site. At high field, for an axially symmetric bond in an axially ordered system, these transitions are split by 3e2qQ AVQ = 4h (1 -3 cos2)Sz. [1] e2qQ/h is a constant for a given bond type (170 kHz for deuterium bound to aliphatic carbons), 6 is the angle between the bond and averaging axis, and Sz is an order parameter (7). It is clear that information concerning orientation of molecular bonds or molecular order can be extracted from observation of deuterium spectra.Most applications of deuterium spectroscopy to date have used a known molecular geometry to extract order parameters. In a few liquid crystal studies, molecular geometries have been deduced (8)(9)(10)(11) Approximately 15 mg of mannose in 0.04 ml of H20 was added to 1.5 ml of this phase. The sample in a 10 mm NMR tube was placed in an 11.7-T superconducting magnet and allowed to equilibrate at 318 K for -1 hr...

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“…The interest in the preparation of polymer aggregates and self-assembly particles has increased enormously in the past decades [1][2][3][4] . Block copolymers is an interesting type of materials due to their well-defined structures and morphological behaviour.…”

Section: Introductionmentioning

confidence: 99%

Polymer aggregates formed by polystyrene-block-poly(4-vinyl-pyridine) functionalized with rhenium(I) 2,2′-bipyridyl complexes

Hou

Chan

1999

Macromol. Rapid Commun.

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SUMMARY: Some metal containing block copolymers derived from polystyrene-block-poly(4-vinylpyridine) were synthesized. The complexation was achieved by reacting the poly(4-vinylpyridine) block with 2,29-bipyridyl(tricarbonyl)rhenium(I) chloride in the presence of silver perchlorate. The resulting polymer metal complexes are able to form micelles in different solvent systems. The morphologies were studied by transmission electron microscopy, and the structure of the micelles was found to be solvent dependent.

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New lyotropic liquid crystals composed of finite nonspherical micelles

Cited by 225 publications

References 19 publications

The effects of high temperatures (29–123 °C) on critical micelle concentrations in solutions of potassium n-octanoate in deuterium oxide: A nuclear magnetic resonance study

The effects of high temperatures (29–123 °C) on critical micelle concentrations in solutions of potassium n-octanoate in deuterium oxide: A nuclear magnetic resonance study

Deuterium NMR as a structural probe for micelle-associated carbohydrates: D-mannose.

Polymer aggregates formed by polystyrene-block-poly(4-vinyl-pyridine) functionalized with rhenium(I) 2,2′-bipyridyl complexes

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