Influence of fluoro substituents on the mesophase behaviour of banana-shaped molecules

Bedel, J. P.; Rouillon, J. C.; Marcerou, J. P.; Laguerre, Michel S.; Nguyen, H. T.; Achard, M. F.

doi:10.1039/b201467j

Cited by 68 publications

(41 citation statements)

References 22 publications

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“…b) Switching current response at T = 115 8C in a 10-mm thick noncoated indium tin oxide (ITO) cell (EHC, Japan) on applying an alternating normal (1 Hz) and modified triangular-wave voltage. [11] that is, the polar FE state seems to be stable (or longliving metastable) under the experimental conditions. These results indicate a bistable switching process, that is, a direct switching between two different polar FE states without a nonpolar AF state at zero voltage (FE switching).…”

Section: Methodsmentioning

confidence: 96%

Liquid‐Crystalline Quaternary Block Molecules Incorporating Bent‐Core Units

et al. 2006

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Section: Methodsmentioning

confidence: 96%

Liquid‐Crystalline Quaternary Block Molecules Incorporating Bent‐Core Units

et al. 2006

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“…Therefore, it is also called tristable switching; that is, switching occurring among one AF ground state and two metastable FE states. Some nonsilylated bent-core molecules have been reported to exhibit FE switching mesophases [96,101,[104][105][106][107][108][109][110][111][112][113][114] (see FE switching for silylated bent-core molecules later). This switching takes place between the two energetically identical polar states with opposite chirality or the two opposite orientations of the same state ( Fig.…”

Section: Field-driven Bent-core Molecular Switchingmentioning

confidence: 99%

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Zhang¹

2013

Intelligent Stimuli‐Responsive Materials

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The three classic states of matter are well known and ubiquitous in everyday life: solid, liquid, and gas. Liquid crystals (LCs), an intermediate state between solid crystal and isotropic liquid, constitute a new fascinating class of condensed soft matter uniquely combining both fluidity and long-range order. The fluid-like mobility enables LCs to be switchable under external stimuli, and crystal-like long-range order bestows anisotropic physical properties on LCs. LCs can be divided into two main classes: thermotropic and lyotropic. Thermotropic LCs consist of individual molecules (or ion pairs) and exhibit phase transitions with the change of temperature. In this case, temperature is the fundamental thermodynamic factor determining mesophase formation. Lyotropic LCs are a special type of solution system that can form mesophases as a function of both temperature and concentration of LC molecules. The building block of a lyotropic phase is an aggregate (called a micelle) formed via self-assembly of many molecules (typically on the order of 100). Examples of LCs can be found both in the natural world and in technological applications. Thermotropic LCs find 189 190 ELECTRIC-AND LIGHT-RESPONSIVE BENT-CORE LIQUID CRYSTALS a wide variety of uses in displays, and an important example of lyotropic LCs is cell membranes formed by amphiphilic lipids. Surfactants in water (i.e., soap water) constitute another useful example of lyotropic LCs. Although the majority of LCs are organic molecules, there exist many LC materials incorporating metals into organic anisotropic molecules [1-3]. These organic-inorganic hybrid LC materials are described as metallomesogens and are recently called metallotropic LCs [4] as distinguished from two main LC classes. In fact, metallomesogens can be classified as either thermotropic or lyotropic LCs depending on their composition and conditions. However, it should be noted that metallomesogens offer a material platform to incorporate magnetic, electronic, optical, redox, and catalytic properties common to inorganic materials into LCs.Although thermotropic LCs have been known to scientists for over 100 years since a discovery by the Austrian botanical physiologist Friedrich Reintizer in 1888, it was only in the late 1960s that they began to be used in display applications. Today, they are best known for their exceptionally successful commercial applications in flat panel display products such as TVs, smart phones, computer displays, and digital projectors. Although today's LC display technology is becoming very advanced, LC materials used in display devices possess the simplest nematic (N) phase and their molecules have been variants on simple rod shapes (Fig. 6.1a). Besides nematic phases, LCs can exhibit other phases: smectic (Sm), columnar (Col), and cubic phases, depending on the orientational or positional orders of their molecules. Nematic phases have only long-range orientational order, smectic mesophases exhibit one-dimensional (1D) positional order and form two-dimensional (2D) layered ...

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“…Interestingly, a fluorine substituent which is ortho to the terminal n-alkoxy chain in symmetrical compounds induces ferroelectric mesophases [9][10][11][12][13], especially for longer terminal chain lengths. It is of interest, therefore, to explore other structural requirements for obtaining the rarely observed ferroelectric mesophases in achiral bent-core compounds.…”

Section: -N-dodecyloxybenzoyloxy-4-benzoic Acid Bmentioning

confidence: 99%

“…As is well known, fluorine has been used as a lateral substituent for modifying mesomorphic properties. In fact fluorine is used as a lateral substituent on the central as well as outer phenyl rings, which has resulted in new mesophases and mesophase sequences [9][10][11][12][13]. In all these systems, fluorine was substituted symmetrically on both arms of the bent-core compounds.…”

Section: Introductionmentioning

confidence: 99%

Fluorine-substituted unsymmetrical bent-core mesogens derived from resorcinol

Murthy

2004

Liquid Crystals

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Forty new bent-core compounds, unsymmetrically substituted about a central phenyl ring, were investigated for their mesomorphic properties. The effect of fluorine substituents in different positions of the phenyl rings of one of the arms of the bent-core compounds on the mesophases were examined in detail. Most of the compounds exhibit the lamellar antiferroelectric B 2 mesophase. The mesophases were investigated by textural observation by polarizing microscopy, differential scanning calorimetry, X-ray diffraction and electrooptical studies.

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Influence of fluoro substituents on the mesophase behaviour of banana-shaped molecules

Cited by 68 publications

References 22 publications

Liquid‐Crystalline Quaternary Block Molecules Incorporating Bent‐Core Units

Liquid‐Crystalline Quaternary Block Molecules Incorporating Bent‐Core Units

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Fluorine-substituted unsymmetrical bent-core mesogens derived from resorcinol

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