Induced Smectic Phases II. Influence of the Amino Substituent on the Induction of Smectic Phases

1981 ◽  
Vol 36 (10) ◽  
pp. 1086-1091 ◽  
Author(s):  
F. Schneider ◽  
N. K. Sharma

The diagrams of state have been studied for some liquid crystal mixtures which show the induction of smectic phases. Each of the systems studied contains one component with an amino group which influences the polarity and the electron donor property of the molecules. The discussion of the diagrams of state, of the thickness of the smectic layers and of the colours of the mixtures, which indicate the formation of CT complexes, shows that existing models can not explain the induction of smectic phases.

Soft Matter ◽  
2016 ◽  
Vol 12 (12) ◽  
pp. 3103-3109 ◽  
Author(s):  
Shin-ya Sugisawa ◽  
Yuka Tabe

1978 ◽  
Vol 45 (3) ◽  
pp. 221-229 ◽  
Author(s):  
M. Bock ◽  
G. Heppke ◽  
E. J. Richter ◽  
F. Schneider

1978 ◽  
Vol 33 (9) ◽  
pp. 1077-1084 ◽  
Author(s):  
B. Engelen ◽  
F. Schneider

Phase diagrams of mixtures of terminal polar and terminal non-polar liquid crystals that exhibit smectic phases with very large ranges of stability are presented. X-ray studies show that the in­duced phases are of type SA, SB or SE. The determination of the layer thickness shows that the induced smectic phases are composed of monolayers, whereas the terminal polar components are composed of bilayers. A model for the formation of the induced smectic phases is proposed.


1978 ◽  
Vol 45 (3-4) ◽  
pp. 221-229 ◽  
Author(s):  
M. Bock ◽  
G. Heppke ◽  
E. J. Richter ◽  
F. Schneider

2011 ◽  
Vol 134 (12) ◽  
pp. 124508 ◽  
Author(s):  
Tsang-Min Huang ◽  
Kathleen McCreary ◽  
Shila Garg ◽  
Thein Kyu

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).


1978 ◽  
Vol 3 ◽  
pp. 403-407 ◽  
Author(s):  
B. Engelen ◽  
G. Heppke ◽  
R. Hopf ◽  
F. Schneider

1981 ◽  
Vol 36 (1) ◽  
pp. 62-67 ◽  
Author(s):  
F. Schneider ◽  
N. K. Sharma

The diagrams of state of mixtures of 4-n-alkyloxybenzylidene-4'-n-butylanilines with 4-n- alkyl- and 4-n-alkyloxy-4'-cyanobiphenyls are studied. The mixtures form induced smectic phases of type SA, SB and SE. In all three smectic phases the thickness of the smectic layers agrees with the mean values of the molecular lengths. In most cases the induced SA phases do not show uninterrupted miscibility with the SA phases of the pure components. For instance, the system 40 • 4/8 CBP exhibits three separate SA phase areas. The maximum transition temperatures of the induced smectic phases increase with increasing chain length of the azomethines, but remain constant in case of the SA and SB phases or even decrease in case of the SE phases with increasing chain length of the cyanobiphenyls


1994 ◽  
Vol 08 (22) ◽  
pp. 3051-3082 ◽  
Author(s):  
CHRISTIAN BAHR

Freely-suspended films of smectic liquid crystals can be regarded as membranes consisting of a stack of an integral number of molecular (smectic) layers with the layer planes being parallel to the two free surfaces. Because of their variable thickness (between thousands and only two layers) and the large variety of phase transitions between different smectic phases, freely-suspended films are excellent systems to study the influence of the dimensional cross-over from three to two dimensions on phase transitions. Further, because the free surface of a liquid crystal has a strong ordering effect (contrary to solids which exhibit generally surface-induced disorder), freely-suspended films are well-suited for the study of the effect of enhanced surface order on phase transitions. A review of the corresponding experimental work is given.


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