摘要:

One series of 4-n-octyl-N-(4-X-benzylidene)anilines and two series of polar orthopalladated complexes derived from these of type Pd2(μ-Y)2p-X-C6H3-CH = N-C6H4-C8H172;X: -H, -F, -Cl, -Br, -NO2, -CN, -CH3, -OCH3, -CF3, -COOCH3, -OCOCH3and -OCOQH5;Y: -OAc and -Cl; have been synthesized and their mesogenic properties studied. In the polar Schiff bases used as organic ligands, the polar end group determines both the presence of the mesophase and the type of mesophase exhibited. In the complexes, however, it is the central structure of the molecule that practically always determines mesogenic behaviour. No acetato-bridged complex is mesogenic. All the chloro-bridged complexes, however, show mesogenic behaviour. All these compounds show smectic A mesophases with the exception of the CN compound, which only exhibits a nematic mesophase.

ISSN:0267-8292    

DOI:10.1080/02678298808086568

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The concentration profile of a cholesteric compound diffusing into a nematic liquid crystal is observed with optical methods. We propose new experimental initial and boundary conditions which allow a more accurate mathematical solution of the differential equation involved. A numerical approach is applied to compute the concentration profiles with a concentration dependent diffusion constant. Diffusion is found to decrease with the shorter pitch length.

ISSN:0267-8292    

DOI:10.1080/02678298808086569

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An X-ray scattering study is presented of the lamellar/nematic/isotropic sequence in the lyotropic system DACI/H2O/NH4Cl. The whole reciprocal space of monocrystalline samples oriented in magnetic fields are reconstructed from their two dimensional sections on photographic films. Intense diffuse scatterings are observed in the lamellar phase, around and away from the Bragg spots. Their evolution close to the lamellar/nematic transition reveals the presence of intense structural fluctuations. They take place over temperature ranges which are significantly greater than those associated with the smectic/nematic transitions in thermotropic liquid crystals. A similar situation is observed in the isotropic phase in the vicinity of the nematic/isotropic transition.

ISSN:0267-8292    

DOI:10.1080/02678298808086570

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Analytical expressions are given for the propagation constant through an homogeneous liquid crystal, following the 4 × 4 matrix formulation of Berreman. Also propagation through polarizers can be calculated analytically; it is a special case of a situation described by Teitler and Henvis.

ISSN:0267-8292    

DOI:10.1080/02678298808086571

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In a liquid-crystalline cubic phase the kinetics of the luminescence induced by pulsed excitation of a luminescing dopant has been studied. The influence of the molecular reorientation on the decay kinetics of the polarized components of the light has been investigated. The correlation times of the molecular reorientation and the magnitude of the local order parameter have been determined.

ISSN:0267-8292    

DOI:10.1080/02678298808086572

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0267-8292    

DOI:10.1080/02678298808086573

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0267-8292    

DOI:10.1080/02678298808086557

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor