摘要:

In order to investigate the relation between molecular structure and liquid crystal properties, structural studies are carried out on sphere like mesogen tetrasubstituted tribenzosilatrane using PM3 semi empirical calculations. PM3 results show that the corresponding terminal cyano or chloro group compounds (alkyl R2replaced by CN or R1by Cl) have much bigger dipole moment or anisotropy of polarizability and like sphere much better than alkyl compounds. Cyano or chloro compounds are probably better candidates for sphere like mesogens.

ISSN:1058-725X    

DOI:10.1080/10587259808045511

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A convenient method of obtaining 4′-(trans-4-pentyl-cyclohexyl)-4-cyanobiphenyl from valeryl chloride, cyclohexene and biphenyl is described. The total yield is 4.1%.

ISSN:1058-725X    

DOI:10.1080/10587259808045512

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The phase transition curves of a multi-component TN liquid crystal mixture (TN88-1) and a multi-component cholesteric liquid crystal mixture (Ch88-2) were plotted by a differential scanning calorimeter. The phase transition temperature and phase transition heat were obtained from the DSC curves. The results show that the components of TN88-1 are compatible and they can form a stable mixture with CB15 chiral liquid crystal. The components of Ch88-2 are not compatible and Poly (MMA-BMA) can greatly improve their compatibility.

ISSN:1058-725X    

DOI:10.1080/10587259808045513

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

New liquid crystals induced by intermolecular hydrogen bonding between 4-[3, 4, 5-tridocyloxy benzoyloxy)-4′-stilbazole (3DBSZ) and malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, maleic acid, fumaric acid, 3,4,5,-tridocyloxy-benzoic acid(3DBA) respectively were prepared, their liquid crystalline properties were investigated by using DSC, polarized optical microscopy and wide-angle X-ray diffraction. The results show that most of the complexes exhibit column phases. Furthermore, a new room temperature column complex was induced by the intermolecular hydrogen bonding between 3DBSZ and 3DBA.

ISSN:1058-725X    

DOI:10.1080/10587259808045514

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Preparation and analysis of sodium decylsulphate, as well as the elaboration of a ternay and a quaternary phase diagram are here presented. The lyomesophases were studied by: polarizing microscopy, small angle X-ray scattering, densimetry and refractometry. The results will be used as basis of comparison in subsequent articles for the related surfactants sodium decylphosphate and sodium decylsulphonate in lyotropic systems.

ISSN:1058-725X    

DOI:10.1080/10587259808045515

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Preparation and analysis of sodium decylphosphate, and elaboration of the binary phase diagram with water as solvent are presented. Lyomesophases isotropic, nematic calamitic and hexagonal are present and were studied by polarizing microscopy, small angle x-ray scattering, densimetry and refratometry. The results are compared with a related surfactant system, sodium decylsulphate.

ISSN:1058-725X    

DOI:10.1080/10587259808045516

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Preparation and analysis of sodium decylsulphonate (SDSNATE), as well as the elaboration of the ternary and quaternary phases diagram are here presented. The lyomesosphases were studied by: polarizing microscopy, small angle X-ray scattering, densimetry and refratometry. We compare the present results on the SDSNATEsystems to sodium decylsulphate systems and perhaps the most important point is that the SDSNATEis free of hydrolysis for all mesomorphic purposes, i.e. the SDSNATEis thermally stable.

ISSN:1058-725X    

DOI:10.1080/10587259808045517

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In this work the dielectric results obtained by time domain spectroscopy for two highly ordered smectic phases of didodecyldimethyl-ammonium bromide are presented. High temperature SmB phase exhibits freedom of molecular reorientation around the long molecular axis with the relaxation time of the order of 100 ps. Upon the transition to the lower temperature biaxial smectic phase the reorientation around the long axis becomes restricted. Dielectric spectra of the system studied are complex with the Cole-Cole distribution parameter of 0.4, which indicates merging of a few molecular processes originating from intra- and intermolecular stochastic motions.

ISSN:1058-725X    

DOI:10.1080/10587259808045518

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The liquid crystal, 4′-cyano-4-biphenyl[4-(4-pentenyloxy)] benzoate (CBPB) has been chemically bonded to silica and the resulting material's interfacial properties examined by Fourier transform infrared spectroscopy. The spectral features of the nitrile stretching region for the chemically anchored system were significantly less complex than those obtained from samples of silica physically coated with CBPB. Further when CBPB was physically coated onto the chemically modified surface, its interactions with the substrate were reduced significantly.

ISSN:1058-725X    

DOI:10.1080/10587259808045519

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Experimental electron diffraction patterns and high resolution images were used to determine the space group and unit cell dimensions of 2,3,6,7,10,11-hexakispentyloxytriphenylene. Subsequently the molecular conformation was calculated by energy minimized package in Cerius2. Using this method, we got the HPT crystal structure: space group: P6/mmm; lattice type: hexogonal; the lattice parameters area = b= 20.3 Å,c= 3.52 Å, α = β = 90°, γ = 120°. The core of HPT is not perpendicular to the column. The angle betweenaaxis and HPT core plane is 9° which cannot be seen inb-cprojection. The simulated ED patterns and HREM images are good agreement with the experimental ED patterns and HREM images.

ISSN:1058-725X    

DOI:10.1080/10587259808045520

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor