Dependence of the electrooptical properties of polymer-dispersed vertical aligned liquid crystals on the surface affinity of the liquid crystal and monomer

2014 ◽  
Author(s):  
Hyojin Lee ◽  
Ji-Hoon Lee ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Polymer Dispersed ◽  
Electrooptical Properties

scholarly journals Holographic Polymer-Dispersed Liquid Crystals: Materials, Formation, and Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-52 ◽  
Author(s):  
Y. J. Liu ◽  
X. W. Sun
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Refractive Index Profile ◽  
Single Step ◽  
Fast Switching ◽  
Polymer Dispersed Liquid Crystal ◽  
Current State ◽  
Index Matching ◽  
Polymer Dispersed ◽  
Materials Used

By combining polymer-dispersed liquid crystal (PDLC) and holography, holographic PDLC (H-PDLC) has emerged as a new composite material for switchable or tunable optical devices. Generally, H-PDLC structures are created in a liquid crystal cell filled with polymer-dispersed liquid crystal materials by recording the interference pattern generated by two or more coherent laser beams which is a fast and single-step fabrication. With a relatively ideal phase separation between liquid crystals and polymers, periodic refractive index profile is formed in the cell and thus light can be diffracted. Under a suitable electric field, the light diffraction behavior disappears due to the index matching between liquid crystals and polymers. H-PDLCs show a fast switching time due to the small size of the liquid crystal droplets. So far, H-PDLCs have been applied in many promising applications in photonics, such as flat panel displays, switchable gratings, switchable lasers, switchable microlenses, and switchable photonic crystals. In this paper, we review the current state-of-the-art of H-PDLCs including the materials used to date, the grating formation dynamics and simulations, the optimization of electro-optical properties, the photonic applications, and the issues existed in H-PDLCs.

scholarly journals Multifrequency Driven Nematics

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 275 ◽  
Author(s):  
Noureddine Bennis ◽  
Jakub Herman ◽  
Aleksandra Kalbarczyk ◽  
Przemysław Kula ◽  
Leszek R. Jaroszewicz
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Fields ◽  
Dielectric Anisotropy ◽  
Dielectric Measurements ◽  
Frequency Tunability ◽  
Frequency Tunable ◽  
Electrooptical Properties ◽  
Crystal Characterization

Liquid crystals act on the amplitude and the phase of a wave front under applied electric fields. Ordinary LCs are known as field induced birefringence, thus both phase and amplitude modulation strongly depend on the voltage controllable molecular tilt. In this work we present electrooptical properties of novel liquid crystal (LC) mixture with frequency tunable capabilities from 100Hz to 10 KHz at constant applied voltage. The frequency tunability of presented mixtures shown here came from composition of three different families of rodlike liquid crystals. Dielectric measurements are reported for the compounds constituting frequency-controlled birefringence liquid crystal. Characterization protocols allowing the optimum classification of different components of this mixture, paying attention to all relevant parameters such as anisotropic polarizability, dielectric anisotropy, and dipole moment are presented.

Strong CPL of achiral liquid crystal fluorescent polymer via the regulation of AIE-active chiral dopant

2020 ◽  
Vol 56 (84) ◽  
pp. 12829-12832
Author(s):  
Kerui Liu ◽  
Yihao Shen ◽  
Xiaojing Li ◽  
Yu Zhang ◽  
Yiwu Quan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cholesteric Liquid Crystals ◽  
New Strategy ◽  
Polymer Dispersed ◽  
Fluorescent Polymer ◽  
Ternary Polymer

Strong CPL induced by ternary polymer dispersed cholesteric liquid crystals (PD-CLCs) can deliver a new strategy for designing excellent CPL materials.

Electrically switchable reflection gratings in polymer dispersed liquid crystals

1999 ◽  
Vol 559 ◽  
Author(s):  
L. V. Natarajan ◽  
R. L. Sutherland ◽  
V. P. Tondiglia ◽  
S. Siwecki ◽  
R. Pogue ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Low Voltage ◽  
Blue Shift ◽  
Maximum Efficiency ◽  
Acrylate Monomer ◽  
Polymer Dispersed ◽  
Reflection Gratings ◽  
Grating Formation

ABSTRACTElectrically switchable volume reflection holograms were written by inhomogeneous illumination of a prepolymer syrup containing a nematic liquid crystal and a multifunctional acrylate monomer. Switchable holograms are diffractive optics structures and the diffraction efficiency can be controlled by the application of an electric field. Reflection gratings with grating spacing varying between 0.16-0.27 µm were made during the phase separation of liquid crystals from the fast curing prepolymer syrup. The reflection efficiency of the holograms were electrically modulated with the applied field of ∼10-15V/µm. Real time study of the grating formation revealed that the maximum efficiency is reached in ∼15 seconds. The shrinkage of the host polymer during grating formation resulted in the blue shift of the reflection notch. The response time of the grating in an electric field is ∼50 µs. Low voltage scanning electron microscope studies showed the presence of discrete nematic droplet domains of sizes 30-60 nm in liquid crystal rich region.

Side-chain liquid-crystal epoxy polymer binders for polymer-dispersed liquid crystals

1992 ◽  
Vol 25 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Liang Chy Chien ◽  
C. Lin ◽  
David S. Fredley ◽  
James W. McCargar
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Epoxy Polymer ◽  
Side Chain ◽  
Polymer Binders ◽  
Polymer Dispersed Liquid Crystals ◽  
Polymer Dispersed
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