Electro-Optics of Polymer-Dispersed Liquid Crystal Materials

1996 ◽  
Vol 425 ◽  
Author(s):  
Paul S. Drzaic
Keyword(s):  
Liquid Crystal ◽  
Chemical Nature ◽  
Film Structure ◽  
Film Properties ◽  
Polymer Dispersed Liquid Crystal ◽  
Crystal Polymer ◽  
Scattering Effects ◽  
Polymer Dispersed ◽  
The Relationship

AbstractThe electro-optical properties of polymer dispersed liquid crystal (PDLC) materials depend on both the chemical nature of the liquid crystal and polymer, as well as the morphology of the liquid crystal/polymer composite. The relationship between several aspects of film structure and PDLC film properties are described, emphasizing scattering effects and reorientation fields. In particular, the idea of relative orientation of neighboring droplets as controlling light scattering, and the role of anchoring in determining film voltages, are highlighted.

Hidden Gratings in Holographic Liquid Crystal Polymer-Dispersed Liquid Crystal Films

2018 ◽  
Vol 10 (15) ◽  
pp. 13107-13112 ◽  
Author(s):  
Luciano De Sio ◽  
Pamela F. Lloyd ◽  
Nelson V. Tabiryan ◽  
Timothy J. Bunning
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Polymer ◽  
Liquid Crystal Films ◽  
Polymer Dispersed Liquid Crystal ◽  
Crystal Polymer ◽  
Crystal Films ◽  
Polymer Dispersed

scholarly journals Light-addressable liquid crystal polymer dispersed liquid crystal

2017 ◽  
Vol 7 (5) ◽  
pp. 1581 ◽  
Author(s):  
Luciano De Sio ◽  
Elena Ouskova ◽  
Pamela Lloyd ◽  
Rafael Vergara ◽  
Nelson Tabiryan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Polymer ◽  
Polymer Dispersed Liquid Crystal ◽  
Crystal Polymer ◽  
Polymer Dispersed

Cavity Morphology of Polymer Dispersed System Utilizing Atomic Force Microscopy

2001 ◽  
Vol 709 ◽  
Author(s):  
Adam K. Fontecchio ◽  
Gregory P. Crawford ◽  
David Content
Keyword(s):  
Atomic Force Microscopy ◽  
Liquid Crystal ◽  
Liquid Crystal Polymer ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Polymer Dispersed Liquid Crystal ◽  
Atomic Force ◽  
Crystal Polymer ◽  
Polymer Dispersed ◽  
Polymer Alignment

ABSTRACTHolographically-formed Polymer Dispersed Liquid Crystal have been imaged using atomic force microscopy (AFM) tapping techniques to study the droplet cavity morphology. Reflection-mode Bragg gratings were created using a 532 nm beam expanded laser to holographically form a grating structure within the liquid crystal / polymer film. The films were removed from their glass substrates prior to imaging by an atomic force microscope, and the digital files were analyzed. The surface structure is not smooth, as anticipated, but contains cavities with a dimpled morphology. We report our investigations and analysis including AFM images, image analysis, and liquid crystal / polymer alignment considerations.

A voltage measurement system based on fiber loop cavity ring-down technology using polymer dispersed liquid crystal film as sensing device

2017 ◽  
Vol 40 (7) ◽  
pp. 2303-2309 ◽  
Author(s):  
Qi Wang ◽  
Wanming Zhao ◽  
Jin Li ◽  
Haifeng Hu ◽  
Yong Zhao
Keyword(s):  
Liquid Crystal ◽  
Measurement System ◽  
Film Structure ◽  
Signal Loss ◽  
Voltage Measurement ◽  
External Voltage ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed ◽  
Cavity Ring Down ◽  
Fiber Loop

This paper proposed and experimentally demonstrated a high-resolution voltage measurement method based on fiber loop cavity ring-down (FLCRD) technology and polymer dispersed liquid crystal (PDLC) film as the sensing device. In this measurement system, PDLC is made into a film structure used as sensing device to measure external voltage changes, and the experiments were carried out to measure the relationships between light transmittivity of PDLC film and the external voltage. The FLCRD system with optimized structure parameters is obtained by numerical simulation, and the splitting ratios of fiber couplers used in the sensing system are optimized, and an erbium-doped fiber amplifier is used to compensate system signal loss, which has made a lot of improvement in the signal noise ratio and sensitivity. Finally, the experimental results show that the resolution of voltage measurement is 0.29 mV (0.0015%) in the range of 0-60V, which improved the resolution by 10 times compared with the current methods.

A study on the mechanical and morphological behavior of polyurethane-encapsulated cholesteric liquid crystal composite films

2020 ◽  
Vol 33 (7) ◽  
pp. 967-977
Author(s):  
Emine Kemiklioglu ◽  
Uğur Kemiklioğlu ◽  
Onur Sayman
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Composite Films ◽  
Tensile Tests ◽  
Free Standing ◽  
Sem Images ◽  
Molecular Weights ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed ◽  
The Relationship

This study explores the preparation and mechanical behavior of free-standing polymer-dispersed liquid crystal (PDLC) film membranes. Polyurethane (PU) was used as a thermoplastic polymer matrix to form these free-standing film membranes. Cholesteryl oleyl carbonate (COC) and cholesteryl pelargonate were used as liquid crystals (LCs) with different molecular weights. PDLC membranes were produced by casting method after LCs and polymer were mixed in the tetrahydrofuran solvent at room temperature. These membranes were formed at different concentration ratios of polymer and LCs. The relationship among the phase separation, LCs and polymer contents as well as the LCs molecular weights was investigated. The morphological structures of these membranes were studied using scanning electron microscopy (SEM). SEM images exhibited that the shapes of LC droplets embedded in PU matrix were more uniform and smaller than those of the membranes which include LC with lower molecular weight. The mechanical properties of the PDLC membranes were determined by carrying out the tensile tests. It was found that the membranes which include COC LC were more flexible.

scholarly journals Polymer Dispersed Cholesteric Liquid Crystals With a Toroidal Director Configuration under an Electric Field

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 732
Author(s):  
Anna P. Gardymova ◽  
Mikhail N. Krakhalev ◽  
Victor Ya. Zyryanov ◽  
Alexandra A. Gruzdenko ◽  
Andrey A. Alekseev ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Electric Field ◽  
Point Defects ◽  
Structural Response ◽  
Optical Filters ◽  
Response Curves ◽  
Polymer Dispersed Liquid Crystal ◽  
Dichroic Dye ◽  
Polymer Dispersed

The electro-optical properties of polymer dispersed liquid crystal (PDLC) films are highly dependent on the features of the contained liquid crystal (LC) droplets. Cholesteric LC droplets with homeotropic boundaries can form several topologically different orientational structures, including ones with single and more point defects, layer-like, and axisymmetric twisted toroidal structures. These structures are very sensitive to an applied electric field. In this work, we have demonstrated experimentally and by computer simulations that twisted toroidal droplets reveal strong structural response to the electric field. In turn, this leads to vivid changes in the optical texture in crossed polarizers. The response of droplets of different sizes were found to be equivalent in terms of dimensionless parameters. In addition, the explanation of this phenomenon showed a comparison of theoretical and experimental structural response curves aids to determine the shape of the droplet. Finally, we demonstrated that the addition of a dichroic dye allows such films to be used as optical filters with adjustable color even without polarizers.

Kinetics of Droplet Formation in UV-Cured Polymer-Dispersed Liquid Crystal Films

1994 ◽  
Vol 33 (Part 1, No. 5A) ◽  
pp. 2641-2647 ◽  
Author(s):  
Vasilii G. Nazarenko ◽  
Seshu Sarala ◽  
Nelamangala V. Madhusudana
Keyword(s):  
Liquid Crystal ◽  
Droplet Formation ◽  
Liquid Crystal Films ◽  
Polymer Dispersed Liquid Crystal ◽  
Crystal Films ◽  
Polymer Dispersed ◽  
Kinetics Of
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