Nuclear Magnetic Resonance and X-Ray Study of a Rectangular Phase

Gustafsson, Stefan; Quist, Per‐Ola

doi:10.1006/jcis.1996.0337

Cited by 17 publications

(25 citation statements)

References 14 publications

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“…11, inset (A)) can be fitted to the structure having pgg symmetry, with the planes of the ribbons slightly tilted to the longer axis of the rectangular unit cell, as it is shown in the inset (B) of Fig. 11 (27,28). The unit cell parameters for this structure observed in the present system (Fig.…”

Section: )mentioning

confidence: 65%

“…11. This is the typical pattern shown by the R 1 phase (27,28). The peak positions of this SAXS pattern may be fitted to both pgg or cmm symmetries, and the peaks observed in the higher q values are not sufficient for the unambiguous identification of the symmetry.…”

Section: )mentioning

confidence: 87%

“…(W s 50) It is assumed that by increasing the decanol concentration from the H 1 phase, microsegregation of decanol and surfactant takes place and the cylindrical cross sections of the aggregates are distorted to somewhat rectangular or elliptical (ribbon) shapes (27)(28)(29) forming the closely related ribbon (R 1 ) phase. By further increasing of decanol concentration, the L a H phase is formed.…”

Section: Phase Transformation Along Line Bmentioning

confidence: 99%

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Phase Behavior and Effect of Enantiomerism on Potassium N -Dodecanoyl Alaninate/Water/Decanol Systems

Acharya¹,

López‐Quintela²,

Kunieda³

et al. 2003

J. Oleo Sci.

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Section: )mentioning

confidence: 65%

Section: )mentioning

confidence: 87%

Section: Phase Transformation Along Line Bmentioning

confidence: 99%

See 1 more Smart Citation

Phase Behavior and Effect of Enantiomerism on Potassium N -Dodecanoyl Alaninate/Water/Decanol Systems

Acharya¹,

López‐Quintela²,

Kunieda³

et al. 2003

J. Oleo Sci.

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“…The branched-chain polyoxyethylene surfactant C 16 Experiments were carried out at the ID02 high brilliance beamline at the European Synchrotron Radiation Facility (ESRF) 20 in Grenoble (France), using a custom-built high pressure apparatus capable of applying hydrostatic pressures of between 1 and 4000 bar to the sample, with an accuracy of ± 10 bar. This apparatus was designed, built and generously provided by Professor R. Winter, University of Dortmund, and is described in 25 detail by Woenckhaus et al 13 The temperature of the high pressure cell was controlled with a precision of ± 0.2 °C by means of a thermostatable jacket through which circulating water was pumped continuously.…”

Section: Sample Preparationmentioning

confidence: 99%

A lyotropic inverse ribbon phase in a branched-chain polyoxyethylene surfactant: pressure effects

et al. 2011

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A centred-rectangular lyotropic inverse ribbon phase, rarely observed in inverse (type II) systems, has been found in the branched-chain polyoxyethylene surfactant tetradecyloctadecyl-tetraoxyethylene ether (C 14 C 16 EO 4 ) in excess water. This phase is stabilised by the application of hydrostatic pressure. The ratio of the 2-D cell parameters, b/a, is observed to be less than √3 (1.732) over the range of temperatures and 10 pressures studied. The constructed pressure -temperature phase diagram shows that, at high temperatures or low pressures, the inverse ribbon phase converts into an inverse micellar cubic phase of spacegroup Fd3m, and at the opposite extreme, a lamellar gel phase was formed. The lattice parameters of the inverse ribbon phase were found to vary with pressure, with the structure becoming increasingly distorted away from 2-D hexagonal symmetry (b/a = √3) with increasing pressure.

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“…[20][21][22] There have been several reports on the structure of the ribbon phases, mainly suggesting they have the primitive-rectangular (plane group p2gg) and centered-rectangular (plane group c2mm) symmetry. [21,23] However, it is hard to make their small structural difference clear: X-ray scattering techniques give us very limited information about the structures. Using direct observation techniques, such as high-resolution transmission electron microscopy (HRTEM), we have found that a systematic structural change from 2D-hexagonal chiral to 2D-rectangular p2gg to lamellar mesostructure can be controlled by precisely adjusting the basicity of the reaction mixture.…”

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confidence: 99%

A 2D‐Rectangular p2gg Silica Mesoporous Crystal with Elliptical Mesopores: An Intermediate Phase of Chiral and Lamellar Mesostructures

et al. 2008

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Since the pioneering work of Kresge and co-workers, [1,2] much effort has been devoted to surfactant-templated mesoporous materials that display topologies closely related to those observed for lyotropic liquid crystals. Enhanced longrange order introduced by using both charged surfactants and controlling polymerization of the inorganic precursors benefits the further identification and characterization of their periodic mesostructures. So far, various mesophases with three-dimensional (3D) symmetry, such as orthorhombic (Pmmm [3] etc.), tetragonal (P4 2 /mnm, [4] P4/mmm [3] ), hexagonal (P6 3 /mmc [5] ), micellar cubic (Pm 3n, [6,7] Fd 3m, [8,9] Im 3m, [7,10] Fm 3m, [11] Pm 3m, [10] etc.), bicontinuous cubic (Ia 3d, [1,2] Pn 3m [12] ), two-dimensional (2D) symmetry, such as rectangular (c2mm [13] ) and hexagonal (p6mm [1,2,14] ), and onedimensional (1D) symmetry, such as lamellar, [1,2] have been discovered as mesoporous crystals in different synthesis systems. Very recently, chiral mesoporous silica (CMS), with a uniform twisted rodlike morphology and hexagonally ordered chiral channels, was also obtained by using chiral, [15] achiral anionic, [16] and achiral cationic [17][18][19] surfactants as the structure-directing agent. However, the formation mechanism, especially the structural relationship between the chiral and other mesostructures, including 2D-hexagonal, 2D-rectangular and lamellar structures, is less well understood because of the complication of the organic-inorganic co-assembling process and lack of information, such as the "synthesis-space diagram". Additionally, the synthesis of mesoporous crystals with controlled mesostructures is of great importance for fundamental research and development of new catalysts, adsorbents, drug delivery hosts, and nanoreactors. Within the range of liquid-crystal phases in surfactantwater systems, an "intermediate phase" has been used to represent those noncubic phases occurring at compositions between hexagonal and lamellar phases. [20][21][22] Ribbon phases are the intermediate phases that exhibit rodlike surfactant aggregates (micelles) with noncircular cross sections, arranged on a 2D-rectangular lattice. [20][21][22] There have been several reports on the structure of the ribbon phases, mainly suggesting they have the primitive-rectangular (plane group p2gg) and centered-rectangular (plane group c2mm) symmetry. [21,23] However, it is hard to make their small structural difference clear: X-ray scattering techniques give us very limited information about the structures. Using direct observation techniques, such as high-resolution transmission electron microscopy (HRTEM), we have found that a systematic structural change from 2D-hexagonal chiral to 2D-rectangular p2gg to lamellar mesostructure can be controlled by precisely adjusting the basicity of the reaction mixture. HRTEM gave direct evidence for the new particular 2D-rectangular p2gg mesostructural constructions with peculiar packing of elliptical mesopores arranged on a 2D-hexagonal lattice. These have ...

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Nuclear Magnetic Resonance and X-Ray Study of a Rectangular Phase

Cited by 17 publications

References 14 publications

Phase Behavior and Effect of Enantiomerism on Potassium N -Dodecanoyl Alaninate/Water/Decanol Systems

Phase Behavior and Effect of Enantiomerism on Potassium N -Dodecanoyl Alaninate/Water/Decanol Systems

A lyotropic inverse ribbon phase in a branched-chain polyoxyethylene surfactant: pressure effects

A 2D‐Rectangular p2gg Silica Mesoporous Crystal with Elliptical Mesopores: An Intermediate Phase of Chiral and Lamellar Mesostructures

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