Column Correlation in Polycatenar Mesophases

Raïs, Khaoula; Daoud, M.; Gharbia, M.; Gharbi, A.; Nguyen, H. T.

doi:10.1002/1439-7641(20010119)2:1<45::aid-cphc45>3.0.co;2-u

Cited by 20 publications

(2 citation statements)

References 24 publications

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“…Recently, many novel discotic LC systems have been identified, including those with building blocks that are chiral molecules, 14 inverted molecules, 15 tapered molecules, 16 half disc molecules, 17 dendrimers, 18 or symmetric-tapered molecules. 19 Supra-molecular discotic mesophase structures driven by molecular recognition processes through non-covalent interactions have become an interesting research topic and a promising approach for practical applications and scientific challenges. 20,21 Non-covalent interactions include hydrogen (H)-bonding, electrostatic (ion-ion, ion-dipole, and dipoledipole) interactions, p-p stacking interactions, van der Waals interactions, and hydrophobic-hydrophilic effects along with others.…”

Section: Introductionmentioning

confidence: 99%

Phase behaviors and supra-molecular structures of a series of symmetrically tapered bisamides

et al. 2006

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A series of symmetrically tapered 1,4-bis[3,4,5-tris(alkan-1-yloxy)benzamido] benzene bisamides (CnPhBA, where n is the number of carbon atoms in the alkyl chains, n = 10, 12 and 16), was synthesized in order to investigate the effect of alkyl chain length on supra-molecular ordered structures induced by hydrogen (H)-bonding and micro-phase separation. These bisamides consist of a rigid aromatic bisamide core with three flexible alkyl chains at each end of the core. Major phase transitions and their origins in CnPhBA bisamides were studied with differential scanning calorimetry, one-dimensional (1D) wide angle X-ray diffraction (WAXD), infrared spectroscopy, and solid-state carbon-13 nuclear magnetic resonance experiments. The structures of these compounds in different phases were identified using 2D WAXD from oriented samples and were also confirmed by selected area electron diffractions in transmission electron microscopy from stacked single crystals and by computer simulations. All of the CnPhBA bisamides in this series formed a highly ordered oblique columnar (W OK ) phase and a low-ordered oblique columnar (W OB ) phase, similar to a recent report on C14PhBA.1 The two main driving forces in the formation of these two supra-molecular columnar structures were identified: One was the H-bond formation between N-H and CLO groups, and the other was the micro-phase separation between the bisamide cores and the alkyl chains. With increasing the length of alkyl tails, the isotropization temperature decreased, while the disordering temperature of the alkyl tails increased. The 2D lattice structures perpendicular to the columnar axis also increasingly deviated from the pseudohexagonal packing with increasing the alkyl tail length. However, the alkyl tail length did not have a significant influence on the packing along the columnar axis direction. Utilizing polarized optical microscopy, the phase identifications were also supported by the observation of texture changes and molecular arrangements inside of the micro-sized domains.

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Section: Introductionmentioning

confidence: 99%

Phase behaviors and supra-molecular structures of a series of symmetrically tapered bisamides

et al. 2006

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“…1 Following the discovery by Chandrasekhar et al 2 in 1977 of what today is referred to as conventional low molar mass discotic mesophases, a variety of novel columnar LC systems have been identified. Their building blocks range from chiral molecules, 3 inverted molecules, 4 tapered molecules, 5 half disc molecules, [6][7][8] bowl-like 9 (pyramidic, 10 cone-shaped 11 ) molecules, dendrimers 12 and fullerodendrimers, 13 symmetric-tapered molecules, 14,15 hybrid organicinorganic polycatenar 16 or multipode supermesogens 17 and conical (badminton shuttlecock) multiadducts of C60. [18][19][20] From the applications point of view, the general interest in columnar LC phases 1 is based on the versatility they offer for the controllable self-assembly of molecular entities into one-dimensional arrays that can be ordered in the other two dimensions.…”

Section: Introductionmentioning

confidence: 99%

Self-organisation of fullerene-containing conical supermesogens

2008

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Multicolour Self‐Assembled Fluorene Co‐Oligomers: From Molecules to the Solid State via White‐Light‐Emitting Organogels

Abbel

Weegen

Pisula

et al. 2009

Chemistry A European J

104

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Five fluorene-based co-oligomers have been prepared to study their self-assembly in a wide range of concentrations, from dilute solutions to the solid state. Subtle changes to the chemical structures, introduced to tune the emission colours over the entire visible range, induce strong differences in aggregation behaviour. Only two of the fluorescent co-oligomer derivatives self-assemble to form soluble fibrils from which fluorescent organogels emerge at higher concentrations. In contrast, the other compounds form precipitates. Mixed fluorescent co-oligomer systems exhibit partial energy transfer, which allows the creation of white-light-emitting gels. Finally, a mechanism for the hierarchical self-assembly of this class of materials is proposed based on experimental results and molecular modelling calculations.

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Column Correlation in Polycatenar Mesophases

Abstract: Liquid crystals, assembled in hexagonal–columnar mesophases as shown in the picture, were characterized in terms of their mechanical properties towards instability. This information was then used to estimate their characteristic lengths and elasticity. A column correlation was deduced.

Cited by 20 publications

References 24 publications

Phase behaviors and supra-molecular structures of a series of symmetrically tapered bisamides

Phase behaviors and supra-molecular structures of a series of symmetrically tapered bisamides

Self-organisation of fullerene-containing conical supermesogens

Multicolour Self‐Assembled Fluorene Co‐Oligomers: From Molecules to the Solid State via White‐Light‐Emitting Organogels

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