Influence of azo dye concentration on dielectric response in polymer dispersed liquid crystal composites

Önsal, Gülnur; Kocakülah, Gülsüm; Kahyaoğlu, Aliye; Köysal, Oğuz

doi:10.1016/j.molliq.2019.04.030

Cited by 31 publications

(5 citation statements)

References 32 publications

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“…The shape anisotropy is much higher in case of pristine PDLC sample cell which might resulted in higher threshold voltage compared with NPs and (NPs + dye) doped PDLCs. Moreover, dielectric anisotropy of LCs slightly increases with the doping of NPs and dye, accordingly, the reduction of threshold field is expected…”

Section: Resultsmentioning

confidence: 99%

Preparation and electrooptic study of reverse mode polymer dispersed liquid crystal: Performance augmentation with the doping of nanoparticles and dichroic dye

Sharma

Kumar

Chinky

et al. 2019

J of Applied Polymer Sci

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Reported herein, the preparation, morphological, and electrooptic (EO) characterization of reverse mode polymer dispersed liquid crystals (PDLCs) with nematic liquid crystal (LC) and UV curable polymer optical adhesive using polymerization induced phase separation method. The PDLCs are switchable between transparent and opaque states due to the homeotropic and planar alignment of LC in their OFF and ON states of applied voltage, respectively. Further, effect of doping of a fixed concentration of azo dye and silica nanoparticles (NPs) on morphological, EO and response characteristics of same PDLC sample was also analyzed. Experimental results showed that doped reverse mode PDLCs have the higher OFF state optical transmission and boost up in the scattering ON state compared with pristine reverse mode PDLC. The phenomenon is also supported by extinction coefficient and absorption study based on Beer's law. The threshold and operating voltages were found reduced ~1.56 and ~1.73 times for NPs and (NPs + dye) doped reverse mode PDLCs, respectively, along with better contrasts to the pristine reverse mode PDLC. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48745.

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Section: Resultsmentioning

confidence: 99%

Preparation and electrooptic study of reverse mode polymer dispersed liquid crystal: Performance augmentation with the doping of nanoparticles and dichroic dye

Sharma

Kumar

Chinky

et al. 2019

J of Applied Polymer Sci

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“…In dye-doped PDLCs (D-PDLCs), dye molecules were found to increase light absorption and decrease the power necessary for the optic effect [ 87 ]. D-PDLCs have been studied extensively by several groups, and it has been found that a strong microscopic mutual interaction among the dye and LC molecules influenced the LC refractive index, dielectric constant, orientational order and phase transition temperature [ 88 , 89 , 90 , 91 , 92 ].…”

Section: Preparation Of Dye-doped Pdlc Composite Filmmentioning

confidence: 99%

“…SEM images of (f) pure PDLC, (g) PDLC + 1% MR, (h) PDLC + 3% MR and (i) PDLC + 5% MR composites. Reproduced with permission from ref [87]…”

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confidence: 99%

Recent Advances in The Polymer Dispersed Liquid Crystal Composite and Its Applications

et al. 2020

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Polymer dispersed liquid crystals (PDLCs) have kindled a spark of interest because of their unique characteristic of electrically controlled switching. However, some issues including high operating voltage, low contrast ratio and poor mechanical properties are hindering their practical applications. To overcome these drawbacks, some measures were taken such as molecular structure optimization of the monomers and liquid crystals, modification of PDLC and doping of nanoparticles and dyes. This review aims at detailing the recent advances in the process, preparations and applications of PDLCs over the past six years.

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“…Fluorescent dichroic dyes can have very multi-way color changes through the design of the molecular structure [37] and can also be used to obtain various colors through the blending of different dyes [38]. Nowadays, azo dyes [35,39,40] and anthraquinone dyes [41][42][43][44] are the primary substances utilized for dichroic dyes in PDLC films. The doping studies of the above dyes have improved the performance of PDLC in different aspects, but there are limitations to the study of its color richness.…”

Section: Introductionmentioning

confidence: 99%

Research on the Morphology, Electro-Optical Properties and Mechanical Properties of Electrochromic Polymer-Dispersed Liquid Crystalline Films Doped with Anthraquinone Dyes

Zhao

et al. 2023

Crystals

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In this paper, dye-doped polymer-dispersed liquid crystalline (DDPDLC) films were prepared with high mechanical properties and low driving voltage by doping different dichroic anthraquinone dyes. The effects of various dye and doping concentrations on microscopic morphology, electro-optical characteristics, and mechanical characteristics were investigated. The optimal doping concentrations of different dyes were also explored. The results show that the addition of all dyes decreased the contrast ratio (CR) and the transmittance and mechanical properties of the polymer-dispersed liquid crystalline (PDLC) films. Similar mechanisms underlie the effects of solvent red 111 and solvent blue 104, which lower the driving voltages of the PDLC films. With the increasing concentration of the dye, the haze of the films first decreased and then increased after the content of the dye reached a certain level. For PDLC films doped with solvent green 28, the driving voltage and haze increased with the increasing content of the dye. According to different influencing factors, the dye content corresponding to the best performance of solvent red 111, solvent green 28 and solvent blue 104 is 0.8 wt%, 2.0 wt% and 0.3 wt%. Electrochromic PDLC films have been prepared based on the research results of dye content. The mechanical properties, electro-optical properties and microstructures of the films have been studied. The results show that the DDPDLC films could change color by tuning the applied voltages. The research provides a theoretical basis for obtaining PDLC films with a wider color gamut and supports the practical application of visible light camouflage technology in the military.

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Influence of azo dye concentration on dielectric response in polymer dispersed liquid crystal composites

Cited by 31 publications

References 32 publications

Preparation and electrooptic study of reverse mode polymer dispersed liquid crystal: Performance augmentation with the doping of nanoparticles and dichroic dye

Preparation and electrooptic study of reverse mode polymer dispersed liquid crystal: Performance augmentation with the doping of nanoparticles and dichroic dye

Recent Advances in The Polymer Dispersed Liquid Crystal Composite and Its Applications

Research on the Morphology, Electro-Optical Properties and Mechanical Properties of Electrochromic Polymer-Dispersed Liquid Crystalline Films Doped with Anthraquinone Dyes

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