Smectic A-Nematic and Nematic-Isotropic Liquid Transitions in 8CB Liquid Crystal: Comparative Analysis

Author(s):  
J. Font ◽  
J. Muntasell ◽  
J. Li. Tamarit ◽  
E. Rojas
Author(s):  
K.J. Ihn ◽  
R. Pindak ◽  
J. A. N. Zasadzinski

A new liquid crystal (called the smectic-A* phase) that combines cholesteric twist and smectic layering was a surprise as smectic phases preclude twist distortions. However, the twist grain boundary (TGB) model of Renn and Lubensky predicted a defect-mediated smectic phase that incorporates cholesteric twist by a lattice of screw dislocations. The TGB model for the liquid crystal analog of the Abrikosov phase of superconductors consists of regularly spaced grain boundaries of screw dislocations, parallel to each other within the grain boundary, but rotated by a fixed angle with respect to adjacent grain boundaries. The dislocations divide the layers into blocks which rotate by a discrete amount, Δθ, given by the ratio of the layer spacing, d, to the distance between grain boundaries, lb; Δθ ≈ d/lb (Fig. 1).


2006 ◽  
Vol 20 (14) ◽  
pp. 821-833 ◽  
Author(s):  
ARIF NESRULLAJEV ◽  
ŞENER OKTIK

In this work, the effect of thin films on the thermotropic and thermo-optical properties and peculiarities of the phase transitions between the smectic A and isotropic liquid have been investigated. Peculiarities of the heterophase regions of the straight smectic A-isotropic liquid and reverse isotropic liquid-smectic A phase transitions have been studied. Change of morphologic properties of the heterophase regions, shift of the phase transition temperatures and the change of temperature widths of these heterophase regions under thin film influence have been observed.


1991 ◽  
Vol 30 (Part 2, No. 4A) ◽  
pp. L612-L615 ◽  
Author(s):  
Ying-Bao Yang ◽  
Akihiro Mochizuki ◽  
Naoto Nakamura ◽  
Shunsuke Kobayashi

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