Local ordering in lyotropic cholesteric liquid crystals studied by X-ray scattering
نویسندگان
چکیده
2014 X-ray diffraction experiments with lyotropic calamitic-nematic phases and induced lyotropic calamitic-cholesteric phases doped with brucine sulfate and d-octanol are performed. The diffraction pattern of the usual oriented nematic phase is compared with the patterns of the untwisted cholesteric phase. The analysis of the patterns indicate that even in the cholesteric phase the pseudo-lamellar structure is maintained. The different features observed in the diffraction patterns of the nematic and cholesteric phases doped with the brucine sulfate are explained in terms of local deformations of the pseudo-lamellar structure. J. Phys. France 49 (1988) 1301-1306 JUILLET 1988,
منابع مشابه
Particle-stabilized defect gel in cholesteric liquid crystals
Dispersions of colloidal particles in cholesteric liquid crystals form an unusual solid by stabilizing a network of linear defects under tension in the ideal layered structure of the cholesteric. The large length scales of the cholesteric liquid crystals allowed direct observation of the network structure, and its properties were correlated with rheological measurements of elasticity. This syst...
متن کاملSelf-alignment of dye molecules in micelles and lamellae for three-dimensional imaging of lyotropic liquid crystals.
We report alignment of anisotropic amphiphilic dye molecules within oblate and prolate anisotropic micelles and lamellae, the basic building blocks of surfactant-based lyotropic liquid crystals. Absorption and fluorescence transition dipole moments of these dye molecules orient either parallel or orthogonal to the liquid crystal director. This alignment enables three-dimensional visualization o...
متن کاملChiroptical Properties of Cholesteric Liquid Crystals of Chitosan Phenylcarbamate in Ionic Liquids
Chitosan phenylcarbamate (CtsPC) samples were synthesized to have different degrees of substitution (DS) ranging from 2.3 to 3.5, and their lyotropic liquid crystallinity in ionic liquids was investigated. 1-Ethyl-3-methylimidazolium dicyanamide ([C2Mim][N(CN)2]) was found to be a novel solvent for CtsPC, and the concentrated lyotropic system formed a cholesteric liquid-crystalline phase and mo...
متن کاملMeasurement of viscosity of lyotropic liquid crystals by means of rotating laser-trapped microparticles.
We describe a simple microrheology method to measure the viscosity coefficients of lyotropic liquid crystals. This approach is based on the use of a rotating laser-trapped optically anisotropic microsphere. In aligned liquid crystals that have negligible effect on trapping beam's polarization, the optical torque is transferred from circularly polarized laser trapping beam to the optically aniso...
متن کاملN NQR and Orientational Ordering in Smectic Liquid Crystals
Liquid crystals are systems which flow like liquids while retaining the mechanical and optical anisotropy of crystals. On a microscopic level they are characterized by molecular orientational order accompanied by a partial or complete translational disorder of the molecular positions (1~3) • Thermotropic liquid crystals are formed upon heating many anisotropic organic compounds, while lyotropic...
متن کامل