Droplet Size Distribution Effect on the Electro-Optical Properties of Emulsion Type Polymer Dispersed Liquid Crystal

AbstractPolymer-dispersed liquid crystal (PDLC) is a composite material that consists of sub micron-size droplets of liquid crystalline (lc) material dispersed in a polymer matrix. A device is usually assembled by sandwiching PDLC between ITO-coated glass plates. The electro optical properties of such a device can be controlled by the application of electric fields; the device acts as a “switch” for the transmission of light. The transmission of light through the device can be controlled between almost zero and 100% by applying ac electric fields. The dielectric properties of the lc and polymer, shape and size distribution of the lc droplets in the PDLC, amplitude and frequency of the applied electric field are among the important parameters for optimizing the performance of such a device. We have investigated the optical properties of PDLC devices fabricated by using several different phase-separation techniques and different lc/polymer materials. We present results for the switching characteristics of these devices as functions of applied electric fields and the size-distribution of the lc droplets. We also present results that reinforce the influence of the interfacial charges on the optical properties of the PDLC devices.

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Optimization of LC droplet size and electro-optical properties of acrylate-based polymer-dispersed liquid crystal by controlling photocure rate

Journal of Applied Polymer Science ◽

10.1002/app.39558 ◽

2013 ◽

Vol 130 (5) ◽

pp. 3098-3104 ◽

Cited By ~ 13

Author(s):

Jung-Dae Cho ◽

Sang-Sub Lee ◽

Su-Cheol Park ◽

Yang-Bae Kim ◽

Jin-Who Hong

Keyword(s):

Optical Properties ◽

Liquid Crystal ◽

Droplet Size ◽

Polymer Dispersed Liquid Crystal ◽

Polymer Dispersed

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Study on Droplet Size Distribution Effect in the Analysis of Postulated Sodium Spray Fire Events Pertaining to SFR Safety

Proceeding of Proceedings of the 25th National and 3rd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2019) ◽

10.1615/ihmtc-2019.1100 ◽

2019 ◽

Author(s):

S. Muthu Saravanan ◽

P. Mangarjuna Rao ◽

P. Selvaraj

Keyword(s):

Size Distribution ◽

Droplet Size ◽

Droplet Size Distribution ◽

Distribution Effect

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

Polymers ◽

10.3390/polym13050732 ◽

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.

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