Synthesis of liquid crystalline polyacrylates and their use in capillary gas chromatography

Naikwadi, K.P.; Jadhav, A. L.; Rokushika, Souji; Hatano, Hiroyuki; Ohshima, Mitsuyosi

doi:10.1002/macp.1986.021870609

Cited by 27 publications

(4 citation statements)

References 23 publications

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“…The liquid crystalline compound was coated on Gas Chrom Q (1 00-1 20 mesh) and packed into a 2.6 m x 2.6 cm i. d. glass tube. Chromatography was carried out with a Shimadzu gas chromatograph GC-5A equipped with a thermal conductivity detector [22].…”

Section: Methodsmentioning

confidence: 99%

Liquid crystal stationary phases for gas chromatography and supercritical fluid chromatography

Rokushika

Naikwadi

Jadhav

et al. 1985

J. High Resol. Chromatogr.

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Novel monomeric and polymeric liquid crystalline compounds were synthesized as stationary phases for gas chromatography (GC) and supercritical fluid chromatography (SFC). Monomeric liquid crystalline compounds were used in packed column gas chromatography for the separation of isomeric aromatic compounds and insect sex pheromones. Liquid crystalline polymers possess long nematic ranges and a uniform coating was easily achieved in glass and fused silica capillaries, which could stand temperatures up to 25OOC in GC and pressures of 200 MPa at 160OC in SFC. The columns provide excellent selectivity and resolution for fused ring aromatic compounds such as the isomers anthracene and phenanthrerie or triphenylene and chrysene.

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Section: Methodsmentioning

confidence: 99%

Liquid crystal stationary phases for gas chromatography and supercritical fluid chromatography

Rokushika

Naikwadi

Jadhav

et al. 1985

J. High Resol. Chromatogr.

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“…Substantial changes of the polymer properties are expected when substituents are introduced as lateral groups on mesogenic cores. However, very few studies have been performed in this respect, [13][14][15][16] and no systematic investigations are available on the effects of the introduction of several substituents in azobenzene-containing polymers . 12 In the present contribution we report on the synthesis and liquid crystalline properties of a class of polymers containing differently methyl-substituted azobenzene groups.…”

Section: Introductionmentioning

confidence: 99%

Thermotropic and Solution Photoisomerization Properties of Side-Chain Liquid Crystalline Polymers Containing Methyl-Substituted Azobenzene Mesogens

Chiellini

Galli

Altomare

et al. 1992

Molecular Crystals and Liquid Crystals Science and Technology.

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The thermotropic and solution photoisomerization properties of a class of polyacrylates containing differently methyl-substituted azobenzene groups are presented. Methyl-substitution inhibits the tendency to crystallize and causes a dramatic decrease in the stability of the established nematic phases. These effects result from a restriction of the packing capability of the mesogenic groups and a reduction of their length-to-breadth ratio. In dilute solution all polymeric samples undergo trans-to-cis photoisomerization of the azo group upon irradiation in the absorption region of the T + T * electronic transitions. Photoisomerization rate constants are very similar and of the same order of magnitude as those observed for other polymeric systems containing the unsubstituted azobenzene chromophore.

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“…The cumulative structures of the two series with different alkyl substituents ( C1-Cs, Clo) in 4-position of the azobenzene group are represented as shown below: While many examples of side chain thermotropic polymers containing the azobenzene unit are known,' the use of such laterally substituted mesogens has been little investigated. [14][15][16][17] Broad liquid crystalline phases and low softening temperatures are recorded for the prepared polymer series.…”

Section: Introductionmentioning

confidence: 99%

Mesomorphic polyacrylates containing isomeric methyl‐substituted azobenzene mesogens

Angeloni

Caretti

Laus

et al. 1991

J. Polym. Sci. A Polym. Chem.

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The synthesis and characterization are reported of two new series of structurally isomeric polyacrylates containing the azobenzene moiety spaced away from the backbone by a hexamethylene spacer and substituted in 4-position with linear alkoxy groups (C1-C6, Clo) and with a lateral methyl group in 2'-or 3'-position. Thermal optical and X-ray analyses of the prepared polymer samples, with molecular weight ranging from 50 X lo3 to 35 X lo4 Dalton ( M u / M n = 2-3), provide evidences for the establishment of liquid crystalline behavior in the melt in a fairly broad range of temperature. In any case, quenching from the mesophase allows for the lock-in of the liquid crystalline structure in the glassy state. The presence of the lateral methyl-substituents causes a drop as high as 50-100 K in the stability of the mesophase with respect to the corresponding samples of the methyl-unsubstituted series.A parallel depletion of the smectogenic character is also observed. Typical even-odd effects on the isotropization temperature and relevant thermodynamic parameters have been detected along with the formation of interdigitated smectic structures.

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Synthesis of liquid crystalline polyacrylates and their use in capillary gas chromatography

Cited by 27 publications

References 23 publications

Liquid crystal stationary phases for gas chromatography and supercritical fluid chromatography

Liquid crystal stationary phases for gas chromatography and supercritical fluid chromatography

Thermotropic and Solution Photoisomerization Properties of Side-Chain Liquid Crystalline Polymers Containing Methyl-Substituted Azobenzene Mesogens

Mesomorphic polyacrylates containing isomeric methyl‐substituted azobenzene mesogens

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