Smectic translational order parameter in two liquid crystalline compounds

2015 ◽  
Vol 88 (5) ◽  
pp. 540-546
Author(s):  
N. Vinutha ◽  
M.K. Usha ◽  
R. Somashekar ◽  
D. Revannasiddaiah
Keyword(s):  
Order Parameter ◽  
Liquid Crystalline ◽  
Translational Order

scholarly journals Perylene-like Dyes in Liquid Crystalline Media

1996 ◽  
Vol 51 (7) ◽  
pp. 843-850 ◽  
Author(s):  
Ewa Mykowska ◽  
Danuta Bauman
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Order Parameter ◽  
Liquid Crystalline ◽  
Fluorescent Dyes ◽  
Liquid Crystal Display ◽  
Isotropic Phase ◽  
Display Devices ◽  
Electrooptical Properties ◽  
Derivatives Of

Abstract The spectral and electrooptical properties of some dichroic fluorescent dyes (derivatives of 3.4,9,10-perylenetetracorboxylic acid and of 3,4,9-perylenetricarboxylic acid) in isotropic solvents and nematic liquid crystals have been studied. The order parameter of the dyes in the anisotropic matrices has been determined by means of optical spectroscopy methods. Moreover, the influence of the dye addition on the nematic-isotropic phase transition temperature of the pure host has been investigated. It was found that some of the dyes studied can be utilized in guest-host liquid crystal display devices.

scholarly journals Order Parameters, Orientational Distribution Functions and Heliconical Tilt Angles of Oligomeric Liquid Crystals

2019 ◽  
Author(s):  
Richard Mandle ◽  
John W. Goodby
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Tilt Angle ◽  
Order Parameter ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Thermal Evolution ◽  
Order Parameters ◽  
Distribution Functions ◽  
Orientational Distribution

We compare the order parameters, orientational distribution functions (ODF) and heliconical tilt angles of the TB phase exhibited by a liquid-crystalline dimer (CB7CB) to a tetramer (O47) and hexamer (O67) by SAXS/WAXS. Following the N-TB phase transition we find that all order parameters decrease, and while 〈P2 〉 remains positive 〈P4 〉 becomes negative. For all three materials the order parameter 〈P6 〉 is near zero in both phases. The ODF is sugarloaf-like in the nematic phase and volcano-like in the TB phase, allowing us to estimate the heliconical tilt angle of each material and its thermal evolution. The heliconical tilt angle appears to be largely independent of the material studied despite the differing number of mesogenic units.

Thermoassisted Photorecording in Chiral Smectic Azodye Copolymers

2001 ◽  
Vol 709 ◽  
Author(s):  
Mikhail V. Kozlovsky ◽  
Wolfgang Haase ◽  
Matthias Rehahn
Keyword(s):  
Order Parameter ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Holographic Gratings ◽  
Copolymer Films ◽  
Shock Heating ◽  
Mesophase Formation ◽  
Photoinduced Birefringence ◽  
High Diffraction Efficiency ◽  
High Diffraction

ABSTRACTIllumination of photochromic liquid-crystalline (PCLC) copolymer films with polarized light during the mesophase formation has been studied. Both thick pressed and thin spin-coated, the films show prominent increase in photoinduced orientation, as compared with conventional isothermal photorecording. Two methods of the thermoassisted recording have been suggested, one of those with simultaneous cooling of the film and another one after a shock heating and quenching. The photoinduced birefringence, Δnind, and the order parameter of photochromic groups, Sazo, have been measured. The thermally assisted recording produces holographic gratings with high diffraction efficiency, η, up to 20-30%.

Thermal Behaviour of Lymphocyte Membrane: ESR Investigation

1990 ◽  
Vol 45 (9-10) ◽  
pp. 1060-1062 ◽  
Author(s):  
S. Mazzuca ◽  
L. Sportelli
Keyword(s):  
Staphylococcus Aureus ◽  
Plasma Membrane ◽  
Order Parameter ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Human Peripheral Blood ◽  
Electron Spin Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Liquid Crystalline State ◽  
Spin Resonance

Abstract The order parameter, S, of the plasma membrane of in toto human peripheral blood lym­ phocytes was obtained by electron spin resonance spectroscopy in the temperature range 25-41°C. This membrane is completely in the liquid crystalline state above 31 °C. In presence of the antigen ETB from Staphylococcus aureus at the concentration of 4 μ/3 × 107 cells an overall decrease of the order parameter for this membrane is observed. The decrease of 5 is followed by an upwards shift at about 35 °C of the temperature of the liquid crystalline state.

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