Wide nematic range alkenyl diphenyldiacetylene liquid crystals

Wu, Shin‐Tson; Neubert, Mary E.; Keast, S. S.; Abdallah, David G.; Lee, S. N.; Walsh, Margaret E.; Dorschner, T. A.

doi:10.1063/1.1288600

Cited by 40 publications

(22 citation statements)

References 13 publications

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“…A eutectic mixture of just the two fluorinated olefins 10a (X~F, A~B~H, n~2 and 3) (mixture B) gave a nematic phase of about the same range as the standard alkyl mixture (table 7) [28] but a much higher figure of merit and a higher clearing temperature. This figure of merit (FoM~K 11 Dn 2 /c 1 ), where K 11 is the bend elastic constant, Dn is the birfringence and c 1 , is an appropriate rotational viscosity, gives the approximate time-response performance of an LC modulator.…”

Section: Mesomorphic Propertiesmentioning

confidence: 95%

The effect of olefinic terminal chains on the mesomorphic properties of 4,4′-disubstituted diphenyldiacetylenes

et al. 2003

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New diphenyldiacetylenes of the type with A, B~H and/or F; m~0, 1; n~1-4; and X~C n H 2nz1 , F, CF 3 or CN were synthesized and their mesomorphic properties determined by hot stage polarizing microscopy and DSC. When m~0, all of these compounds showed only a nematic phase except when X~CF 3 when both nematic and smectic A phases were seen. Both clearing and melting temperatures were higher than those reported for substitution with the corresponding alkyl chains but the much larger increase in clearing temperatures produced considerably wider nematic phases. Eutectic mixtures of a few of these olefins yielded nematic materials also having much wider temperature ranges and higher clearing temperatures than the eutectic mixtures of the alkyl compounds, while retaining their high birefringence and low viscosities. Such materials are of interest for beam-steering devices. Four of the diacetylenes with m~1 (A, B~H) were also prepared (X~C 6 H 13 , F, n~2, 3). When X was C 6 H 13 (n~2), the nematic range was smaller in the 2-than in the 1-olefin but wider than in the alkyl series. When X~F, either no nematic phase or a monotropic one was observed, whereas the 1-olefins gave a much wider nematic phase. Both transition temperatures were lower than those for the corresponding 1-olefin and alkyl analogues. The compound with X~C 6 H 13 and n~2 had a melting temperature below room temperature.

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Section: Mesomorphic Propertiesmentioning

confidence: 95%

The effect of olefinic terminal chains on the mesomorphic properties of 4,4′-disubstituted diphenyldiacetylenes

et al. 2003

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“…The molecular structures of the bistolane [7][8][9], naphthalene tolane [10], and biphenyl tolane [11,12] we studied are listed as #2-4 in Table 1 and their nematic range is 73.5!150.5, 95.3!135.2 and 185.7!212 C, respectively. These compounds have birefringence in the 0.35 to 0.55 range.…”

Section: Bistolane Naphthalene Tolane and Biphenyl-tolanementioning

confidence: 99%

UV Stability of High Birefirngence Liquid Crystals

Lin

Chang³

et al. 2004

Molecular Crystals and Liquid Crystals

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“…Several high birefringence molecular structures, such as diphenyldiacetylene [4,5], bistolane [6,7], naphthalene tolanes [8], and thiophenyl-diacetylene [9][10][11] have been studied. Recently some of biphenyl-tolane compounds were synthesized and their properties were investigated [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

High Figure-of-Merit Laterally Fluorinated Biphenyltolane-Isothiocyanates

Gauza

Zhao

Cor

et al. 2007

Molecular Crystals and Liquid Crystals

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We have designed, synthesized, and evaluated the physical properties of some high birefringence (Dn) isothiocyanato biphenyl-tolane liquid crystals. These compounds exhibit Dn $ 0.48-0.52 at room temperature and wavelength k ¼ 633 nm. Laterally substituted short alkyl chains and fluorine atom eliminate smectic phase and lower the melting temperature. The moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. A eutectic mixture based on those compounds was formulated and its physical properties evaluated.

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Wide nematic range alkenyl diphenyldiacetylene liquid crystals

Cited by 40 publications

References 13 publications

The effect of olefinic terminal chains on the mesomorphic properties of 4,4′-disubstituted diphenyldiacetylenes

The effect of olefinic terminal chains on the mesomorphic properties of 4,4′-disubstituted diphenyldiacetylenes

UV Stability of High Birefirngence Liquid Crystals

High Figure-of-Merit Laterally Fluorinated Biphenyltolane-Isothiocyanates

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