Surface anchoring and growth pattern of the first-order structural transition in a smectic A liquid crystal

1994 ◽  
Author(s):  
Zili Li ◽  
W. R. Folks ◽  
Oleg D. Lavrentovich
Keyword(s):  
Liquid Crystal ◽  
Growth Pattern ◽  
Structural Transition ◽  
Surface Anchoring ◽  
First Order ◽  
Smectic A

Specific Volume and Ultrasonic Velocity Studies of the Liquid Crystal N-(p-n-hexyloxybenzylidene)-p-n-butylaniline (Hx BBA)

1983 ◽  
Vol 38 (7) ◽  
pp. 762-764 ◽  
Author(s):  
L. V. Choudary ◽  
J. V. Rao ◽  
P. N. Murty ◽  
C. R. K. Murty
Keyword(s):  
Thermal Expansion ◽  
Liquid Crystal ◽  
Ultrasonic Velocity ◽  
Specific Volume ◽  
Velocity Variation ◽  
Velocity Measurements ◽  
First Order ◽  
Smectic A ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Abstract Specific volume and ultrasonic velocity measurements have been carried out on the liquid crystal N-(p-n-hexyloxybenzylidene)-p-n-butylaniline in the isotropic, nematic, smectic A, smectic B and smectic G phases. The variation of the specific volume with temperature shows that the corresponding transitions are of first order. Thermal expansion coefficients have been calculated for all the mesophases. The ultrasonic velocity variation with temperature confirms the transitions.

Freeze-fracture TEM of the helical smectic A* phase

1992 ◽  
Vol 50 (1) ◽  
pp. 278-279
Author(s):  
K.J. Ihn ◽  
R. Pindak ◽  
J. A. N. Zasadzinski
Keyword(s):  
Liquid Crystal ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Freeze Fracture ◽  
Smectic Phase ◽  
Layer Spacing ◽  
Screw Dislocations ◽  
Smectic A ◽  
Smectic Phases ◽  
Discrete Amount

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).

Temperature influence on homogeneous instabilities in stationary shear flow of nematic liquid crystal with weak surface anchoring

2010 ◽  
Vol 7 ◽  
pp. 191-201
Author(s):  
I.Sh. Nasibullayev ◽  
O.V. Urina
Keyword(s):  
Liquid Crystal ◽  
Shear Flow ◽  
Nematic Liquid Crystal ◽  
Effect Of Temperature ◽  
External Fields ◽  
Temperature Influence ◽  
Surface Anchoring ◽  
Weak Surface ◽  
Surface Coupling

Plane stationary shear flow of the nematic liquid crystal with weak surface anchoring is investigated. The effect of temperature, external fields, and the nature of the surface coupling on the formation of orientation instabilities is investigated.

Temperature influence on orientation dynamics of oscillatory Poiseuille flow of nematic liquid crystal

2010 ◽  
Vol 7 ◽  
pp. 172-181
Author(s):  
I.Sh. Nasibullayev ◽  
U.R. Kamaletdinova
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Poiseuille Flow ◽  
External Influence ◽  
Temperature Influence ◽  
Surface Anchoring ◽  
Orientation Behaviour ◽  
Orientation Change ◽  
Low Amplitude ◽  
Flow Plane

In this work is studying temperature influence and surface anchoring in orientation behaviour of oscillatory Poiseuille flow of nematic liquid crystal (NLC) in the plane cell. Without external influence molecules lays along flow plane. Molecules orientation change and caused by this back-flow is studied by low-amplitude decomposition.

scholarly journals Azimuthal Anchoring Strength in Photopatterned Alignment of a Nematic

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 675
Author(s):  
H. Nilanthi Padmini ◽  
Mojtaba Rajabi ◽  
Sergij V. Shiyanovskii ◽  
Oleg D. Lavrentovich
Keyword(s):  
Liquid Crystal ◽  
Point Defects ◽  
Elastic Energy ◽  
Separation Distance ◽  
Thin Layers ◽  
Uv Exposure ◽  
Surface Anchoring ◽  
Anchoring Strength ◽  
Spatially Varying

Spatially-varying director fields have become an important part of research and development in liquid crystals. Characterization of the anchoring strength associated with a spatially-varying director is difficult, since the methods developed for a uniform alignment are seldom applicable. Here we characterize the strength of azimuthal surface anchoring produced by the photoalignment technique based on plasmonic metamsaks. The measurements used photopatterned arrays of topological point defects of strength +1 and −1 in thin layers of a nematic liquid crystal. The integer-strength defects split into pairs of half-integer defects with lower elastic energy. The separation distance between the split pair is limited by the azimuthal surface anchoring, which allows one to determine the strength of the latter. The strength of the azimuthal anchoring is proportional to the UV exposure time during the photoalignment of the azobenzene layer.

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