Fluorescent Hexacatenar Liquid Crystals

1999 ◽  
Vol 560 ◽  
Author(s):  
Ben Hoag ◽  
Douglas L. Gin ◽  
Udo Theissl ◽  
Egbert Zojer ◽  
Guenther Leising
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Emission Spectroscopy ◽  
Liquid Crystalline ◽  
Photophysical Properties ◽  
Optoelectronic Properties ◽  
Blue Luminescence ◽  
Photoluminescence Excitation ◽  
Site Selective

ABSTRACTA novel family of phasmidic liquid crystals incorporating an oligo(ρ-phenylenevinylene) core was produced. These compounds exhibit blue luminescence in both solution and the solid state. The emission profiles are influenced by the degree of organization in the solid state. The snthesis and liquid-crystalline behavior of these compounds will be discussed. Their photophysical properties, as studied by c.w. photoluminescence excitation, emission spectroscopy, and site selective spectroscopy, as well as their optoelectronic properties will be presented.

Fluorescent Hexacatenar Liquid Crystals

1999 ◽  
Vol 558 ◽  
Author(s):  
Ben Hoag ◽  
Douglas L. Gin
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Emission Spectroscopy ◽  
Liquid Crystalline ◽  
Photophysical Properties ◽  
Optoelectronic Properties ◽  
Blue Luminescence ◽  
Photoluminescence Excitation ◽  
Site Selective

ABSTRACTA novel family of phasmidic liquid crystals incorporating an oligo(p-phenylenevinylene) core was produced. These compounds exhibit blue luminescence in both solution and the solid state. The emission profiles are influenced by the degree of organization in the solid state. The snthesis and liquid-crystalline behavior of these compounds will be discussed. Their photophysical properties, as studied by c.w. photoluminescence excitation, emission spectroscopy, and site selective spectroscopy, as well as their optoelectronic properties will be presented.

scholarly journals Synthesis and Characterization of Photoluminescence Liquid Crystals Based on Flexible Chain-Bearing Pentafluorinated Bistolanes

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 603
Author(s):  
Shigeyuki Yamada ◽  
Masaya Sato ◽  
Tsutomu Konno
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Oxygen Atom ◽  
Liquid Crystalline ◽  
Color Change ◽  
Photophysical Properties ◽  
Structure Property ◽  
Flexible Chain ◽  
Structure Property Relationships ◽  
Chiral Nematic

The liquid-crystalline (LC) and photophysical properties of molecules are very sensitive to their electronic and molecular aggregate structures. Herein, to shed light on the structure–property relationships of pentafluorinated bistolane-based photoluminescence (PL) liquid crystals (PLLCs) previously reported by our group, we synthesized pentafluorinated bistolanes with variable flexible chains and evaluated their LC and photophysical properties. The incorporation of an oxygen atom (to afford a 2-methoxyethoxy unit) or an oxygen atom and a methyl group (to afford a 1-methoxyprop-2-oxy unit) into the flexible butoxy chain significantly decreased the temperature of the crystalline-to-LC phase transition, and a chiral nematic phase comprising helical molecular aggregates was observed for the chiral 1-methoxyprop-2-oxy group–bearing bistolane. The synthesized bistolanes exhibited strong blue PL in both solution and crystalline phases; the featuring PL characteristics were maintained in the LC phase (produced by the crystalline-to-LC phase transition) except for a slight PL color change. Thus, it was concluded that the PL behavior of pentafluorinated bistolanes can be modulated by the choice of a suitable flexible chain, and the obtained insights are believed to facilitate the application of PLLCs in thermosensing PL materials.

Controlling Materials Architecture on the Nanometer-Scale: PPV Nanocomposites Via Polymerizable Lyotropic Liquid Crystals

1997 ◽  
Vol 488 ◽  
Author(s):  
Ryan C. Smith ◽  
Hai Deng ◽  
Walter M. Fischer ◽  
Douglas L. Gin
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Liquid Crystalline ◽  
Lyotropic Liquid Crystals ◽  
Nanometer Scale ◽  
General Strategy ◽  
Hexagonal Symmetry ◽  
The Matrix ◽  
Hexagonal Arrangement ◽  
Lock In

AbstractWe have developed a general strategy for the construction of ordered nanocomposites with hexagonal symmetry, using polymerizable lyotropic (i.e., amphiphilic) liquid crystals. In this approach, self-organizing lyotropic liquid-crystalline monomers are used to form an ordered template matrix in the presence of a reactive hydrophilic solution. Subsequent photopolymerization to lock-in the matrix architecture, followed by initiation of chemistry within the ordered hydrophilic domains to afford solid-state fillers, yields the anisotropic nanocomposites. Composites have been synthesized that have a regular hexagonal arrangement of extended poly(p-phenylenevinylene) (PPV) domains, with a regular interchannel spacing of 4 nm. The photoluminescence of these materials is significantly altered from that of bulk PPV. The dimensions of these nanocomposites can be tuned by varying the size of the hydrophobic tails and/or the nature of the counterion associated with the hydrophilic headgroup of the monomer.

scholarly journals Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding

2021 ◽  
Vol 17 ◽  
pp. 124-131
Author(s):  
Subrata Nath ◽  
Alexander Kappelt ◽  
Matthias Spengler ◽  
Bibhisan Roy ◽  
Jens Voskuhl ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Bond Strength ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Systematic Variation ◽  
Mesomorphic Properties

The first example of halogen-bonded fluorescent liquid crystals based on the interaction of iodofluorobenzene derivatives with nitro-cyanostilbenes is reported. The systematic variation of the fluorination degree and pattern indicates the relevance of the halogen bond strength for the induction of liquid crystalline properties. The modular self-assembly approach enables the efficient tuning of the fluorescence behaviour and mesomorphic properties of the assemblies.

Structure-property relations of liquid crystalline polymers

1987 ◽  
Vol 45 ◽  
pp. 460-463
Author(s):  
Linda C. Sawyer
Keyword(s):  
Solid State ◽  
Liquid Crystalline ◽  
Structural Model ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Mechanical Anisotropy ◽  
Structure Property ◽  
Preparation Methods ◽  
Crystalline Polymers ◽  
Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

Liquid-crystalline behaviour and electrorheological effect of phthalocyanine-based ionic liquid crystals

2020 ◽  
pp. 1-10
Author(s):  
Aikebaier Reheman ◽  
Shuangying Hu ◽  
Lianjun Cao ◽  
Danhua Xie ◽  
Guiyang Yan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Electrorheological Effect ◽  
Ionic Liquid Crystals

scholarly journals Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

2019 ◽  
Vol 15 ◽  
pp. 2013-2019 ◽  
Author(s):  
Esther Nieland ◽  
Oliver Weingart ◽  
Bernd M Schmidt
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Visible Light ◽  
Half Life ◽  
Photophysical Properties ◽  
Bathochromic Shift ◽  
Halogen Bonding ◽  
Building Blocks ◽  
Partial Overlap

ortho-Fluoroazobenzenes are a remarkable example of bistable photoswitches, addressable by visible light. Symmetrical, highly fluorinated azobenzenes bearing an iodine substituent in para-position were shown to be suitable supramolecular building blocks both in solution and in the solid state in combination with neutral halogen bonding acceptors, such as lutidines. Therefore, we investigate the photochemistry of a series of azobenzene photoswitches. Upon introduction of iodoethynyl groups, the halogen bonding donor properties are significantly strengthened in solution. However, the bathochromic shift of the π→π* band leads to a partial overlap with the n→π* band, making it slightly more difficult to address. The introduction of iodine substituents is furthermore accompanied with a diminishing thermal half-life. A series of three azobenzenes with different halogen bonding donor properties are discussed in relation to their changing photophysical properties, rationalized by DFT calculations.

Characterization of some mesogenic alkyl 1-thioglycosides

2002 ◽  
Vol 80 (8) ◽  
pp. 1162-1165 ◽  
Author(s):  
B Henrissat ◽  
G K Hamer ◽  
M G Taylor ◽  
R H Marchessault
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Solid State ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
Liquid Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Phases

A series of dodecyl 1-thio-β-D-glycosides has been synthesized and characterized (DSC, NMR, CP MAS, X-ray diffraction) as possible new marking materials with liquid-crystalline properties. These compounds undergo solid to liquid crystal phase transitions at various temperatures, which depend on the nature of the carbohydrate part of the structure. Their liquid-crystalline phases show extreme shear thinning behaviour.Key words: liquid crystal, powder X-ray diffraction, phase transition, thioglycoside, solid-state NMR, marking material

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