scholarly journals Effect of ferroelectric BaTiO3 particles on the threshold voltage of a smectic A liquid crystal

2018 ◽  
Vol 9 ◽  
pp. 824-828 ◽  
Author(s):  
Abbas Rahim Imamaliyev ◽  
Mahammadali Ahmad Ramazanov ◽  
Shirkhan Arastun Humbatov
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Threshold Voltage ◽  
Strong Electric Field ◽  
Dielectric Anisotropy ◽  
Smectic A ◽  
Capacitance Voltage ◽  
Two Factors ◽  
Smectic A Liquid Crystals

The influence of small ferroelectric BaTiO3 particles on the planar–homeotropic transition threshold voltage in smectic A liquid crystals consisting of p-nitrophenyl p-decyloxybenzoate and 4-cyano-4′-pentylbiphenyl were studied by using capacitance–voltage (C–V) measurements. It was shown that the BaTiO3 particles significantly reduce the threshold voltage. The obtained result is explained by two factors: an increase of dielectric anisotropy of the liquid crystals and the formation of a strong electric field near polarized particles of BaTiO3. It was shown that the role of the second factor is dominant. The explanations of some features observed in the C–V characteristics are given.

scholarly journals Hydrophobic gold nanoparticles via silane conjugation: chemically and thermally robust nanoparticles as dopants for nematic liquid crystals

2013 ◽  
Vol 371 (1988) ◽  
pp. 20120256 ◽  
Author(s):  
Javad Mirzaei ◽  
Martin Urbanski ◽  
Heinz-S. Kitzerow ◽  
Torsten Hegmann
Keyword(s):  
Phase Transition ◽  
Gold Nanoparticles ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Threshold Voltage ◽  
Nematic Phase ◽  
Dielectric Anisotropy ◽  
Smectic A ◽  
Gold Nps ◽  
First Time

We examine for the first time how chemically and thermally stable gold nanoparticles (NPs), prepared by a silane conjugation approach, affect both the thermal and the electro-optical properties of a nematic liquid crystal (LC), when doped at concentrations ranging from 0.25 to 7.5 wt%. We find that the octadecylsilane-conjugated gold NPs stabilize both the enantiotropic nematic and the monotropic smectic-A phases of the LC host with a maximum stabilization of 2 ° C for the nematic and 3.5 ° C for the smectic-A phases for the mixture containing 1 wt% of the silanized particles. The same mixture shows the lowest values for the Fréedericksz transition threshold voltage and the highest value for the dielectric anisotropy. Generally, all NP-containing mixtures, except mixtures with NP concentrations exceeding 5 wt%, reduce the threshold voltage, increase the dielectric anisotropy and reduce both rise and decay time; the latter particularly at temperatures at least 10 ° C below the isotropic–nematic phase transition on cooling.

Spatially Resolved Characterization of the Electroclinic Effect in Chiral Smectic a Liquid Crystals

1996 ◽  
Vol 425 ◽  
Author(s):  
J. R. Lindle ◽  
S. R. Flom ◽  
F. J. Bartoli ◽  
A. T. Harter ◽  
R. E. Geer ◽  
...  
Keyword(s):  
Optical Properties ◽  
Angular Distribution ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Tilt Angle ◽  
X Ray ◽  
Smectic A ◽  
Spatially Resolved ◽  
Smectic A Liquid Crystals

AbstractThe electro-optical properties of an electroclinic liquid crystal have been investigated using a spatially resolved technique which measures the birefringence, optical tilt angle and extinction within adjacent stripe domains. A comparison of these results with the data obtained from standard optical and X-ray measurements suggests the presence of substripes or an angular distribution of molecular directors within the stripe domains.

scholarly journals Electrically driven formation and dynamics of Pac-Man solitons in smectic A liquid crystals

2021 ◽  
Author(s):  
Yuan Shen ◽  
Ingo Dierking
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Spatiotemporal Chaos ◽  
Practical Applications ◽  
Smectic A ◽  
Fundamental Science ◽  
Smectic A Liquid Crystals

Electric field driven instabilities of liquid crystals, such as electro-convections, spatiotemporal chaos, backflows, and solitons are of great importance for both fundamental science and practical applications. Here we demonstrate that...

scholarly journals Installation for measuring the dielectric anisotropy of liquid crystals at low frequencies by the bridge method with constant displacement

2021 ◽  
Vol 1198 (1) ◽  
pp. 012006
Author(s):  
S V Kalashnikov ◽  
N A Romanov ◽  
A V Nomoev
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Internal Resistance ◽  
Dielectric Anisotropy ◽  
Dielectric Parameters ◽  
Low Frequencies ◽  
Offset Voltage ◽  
Wide Range ◽  
Ac Current ◽  
Constant Displacement

Abstract Installation designed to measure the dielectric anisotropy in laboratory studies of liquid crystal polymer films is described. The installation operates on the principle of a balanced alternating current (AC) bridge, allowing the application of a direct external current (bias) to the liquid crystal cell. The internal resistance of the direct current (DC) source, which affects the equilibrium condition of the bridge, is compensated. The frequency of the AC current feeding the bridge and the offset voltage of the cell is regulated within a wide range, which makes it possible to study various functional dependences of the dielectric parameters of liquid crystals and their modifiers.Introduction

scholarly journals Undulation instability under shear in smectic A liquid crystals

1982 ◽  
Vol 43 (8) ◽  
pp. 1193-1197 ◽  
Author(s):  
P. Oswald ◽  
S.I. Ben-Abraham
Keyword(s):  
Liquid Crystals ◽  
Smectic A ◽  
Smectic A Liquid Crystals
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