Isomorphiebeziehungen zwischen kristallin-flüssigen Phasen

Demus, D.; Kunicke, G.; Neelsen, J.; Sackmann, H.

doi:10.1515/zpch-1974-0110

Cited by 20 publications

(27 citation statements)

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“…Therefore, the number of molecules forming As shown in gure 3 ( a ), in the two-dimensional IP a cubic unit lattice is not constant and decreases image, the patterns of the Cub II phase often became with increasing T . We shall call this the¯u id spot-like because of the easy growth of fairly large nature of the Cub phases, in that it is similar to the domains [5,7]. This tendency was signi cant for the number of liquid water molecules in a unit volume homologues with smaller n such as n = 15 and 16.…”

Section: Resultsmentioning

confidence: 93%

“…The phase behaviour of they share the common feature of consisting of two ANBC-n and the structure of the CubD phase have been incompatible components, e.g. aliphatic vs aromatic, investigated by optical microscopy [4,5,9,17], refractivity apolar vs polar, or soft vs hard components, with a ratio [6], X-ray di V raction [7,8,12,14,16,21,25,27,28,31], NMR [13,20], viscoelastic measurements [18,23 ], infrared spectroscopy [19,26], adiabatic calorimetry 1448 S. Kutsumizu et al…”

Section: Introductionmentioning

confidence: 99%

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Cubic phases of 4′-n-alkoxy-3′-nitrobiphenyl-4-carboxylic acids (ANBC-n)

Kutsumizu¹,

Morita²,

Ichikawa³

et al. 2002

Liquid Crystals

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The structure of the thermotropic cubic phases of 4 ¾ -n -alkoxy-3 ¾ -nitrobiphenyl-4-carboxylic acids (ANBC-n , where n indicates the number of carbon atoms in the alkoxy group) was studied by X-ray di V raction. For the homologues with n= 15, 16, 17, and 18, the cubic phase was of an Ia 3 d type, whereas the homologues with n = 19, 20, and 21 exhibited an Im 3 m cubic structure; for these seven homologues the same type of cubic structure was observed both on heating and cooling. Further lengthening of the alkoxy chain to n= 22 and 26, however, gave two types of cubic structure in the cubic phase region on heating, one with Im 3 m symmetry in the low temperature region and the other with Ia 3 d symmetry in the high temperature region. On cooling, the two homologues exhibited the Ia 3 d cubic structure only. This is the rst example in the cubic phase region of a series of homologues containing two types of structure, dependent on temperature and n . Such a complicated phase diagram in the cubic region is clearly understood qualitatively in terms of Gibbs free energy-temperature diagrams. The dependence of structural parameters such as the cubic lattice constant on the alkoxy chain length n are also presented and discussed.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Cubic phases of 4′-n-alkoxy-3′-nitrobiphenyl-4-carboxylic acids (ANBC-n)

Kutsumizu¹,

Morita²,

Ichikawa³

et al. 2002

Liquid Crystals

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“…The results presented reveal that the eOE ect of nitro substitution in achiral calamitic liquid crystals on their has been studied in [254][255][256][257][258][259][260][261][262][263][264][265][266][267][268]. The mesomorphic [27,178,[195][196][197][198][199][200][201][202] inter-…”

Section: L Ateral Nitro Substitutionmentioning

confidence: 99%

Nitro substitution in achiral calamitic liquid crystals

Petrov¹,

Shimizu

2001

Liquid Crystals

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“…4 0 -n-alkoxy-3 0 -nitrobiphenyl-4-carboxylic acids (designated as ANBC-n, where n is the number of carbon atoms in the alkoxy groups) are well known for exhibiting thermotropic cubic (Cub) phases [1][2][3][4][5][6][7][8][9][10][11][12][13][14], and two lattice types (Ia3d and Im3m) have been reported, the formation of which is strongly dependent on the alkoxy chain length n. When 15 n 18, the Ia3d-Cub phase is formed, and for 19 n 21, the Im3m type is seen, both on heating and cooling (except for n ¼ 15, where the Cub phase is observed only on the first heating of the virgin sample) [12][13][14]. Since one cubic lattice contains more than one thousand molecules, and thus, it is very difficult to deduce the packing at the molecular level from the lattice dimension and the packing symmetry obtained.…”

Section: Introductionmentioning

confidence: 99%

Cubic Phases of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic Acid (ANBC-22)

Kutsumizu

Yamada

Yano

et al. 2004

Molecular Crystals and Liquid Crystals

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Dilatometric experiments have been performed on 4 0 -n-docosyloxy-3 0 -nitrobiphenyl-4-carboxylic acid (ANBC-22) which exhibits two types of thermotropic cubic phases (Cub I and II) on heating. Although the unit lattices of both Cub I and II, determined by X-ray diffraction measurements, slightly but certainly shrink with increasing temperature, the thermal expansion coefficients in both temperature regions were found to be positive. Thus, this study provided an experimental evidence that the number of molecules constructing the unit lattice of the two Cub phases decreases with temperature. Some aspects of the structural features of the Cub phases are discussed.

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Isomorphiebeziehungen zwischen kristallin-flüssigen Phasen

Cited by 20 publications

References 0 publications

Cubic phases of 4′-n-alkoxy-3′-nitrobiphenyl-4-carboxylic acids (ANBC-n)

Cubic phases of 4′-n-alkoxy-3′-nitrobiphenyl-4-carboxylic acids (ANBC-n)

Nitro substitution in achiral calamitic liquid crystals

Cubic Phases of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic Acid (ANBC-22)

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