Surfactant-doped reverse-mode polymer-dispersed liquid crystal display with enhanced properties

Abstract

In this article, a nonionic surfactant Brij30 has been used to vertical align the negative anisotropic liquid crystal. The surfactant is further used in reverse-mode polymer-dispersed liquid crystal display to enhance the electrooptical properties. This work shows an enhancement of contrast ratio simply with the addition of surfactant. In addition, contact angle and surface free energies have been determined to judge the role of surfactant in control of surface orientation of liquid crystal molecules.

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

“…The key alignments of LCs are homogeneous, homeotropic, and hybrid, which are being utilized for various electrooptic (EO) applications of LC in order to execute the purpose. In recent years, these EO materials based on polymer dispersed liquid crystals (PDLCs) are found advanced with their working operation in reverse mode with homeotropic alignment (HA) of LCs . In reverse mode, PDLCs follow the mechanism of initial transmission of light owing to the homeotropically aligned LCs, whereas electrically tunable scattering of light deals with the transparent to opaque state of the PDLC film.…”

“…Alteration of glass surface by polyvinyl butyral layer, photoalignment, cetyltrimethylammonium bromide coatings on indium tin oxide (ITO) surfaces, rough surfaces for orientational control, and doping of ferromagnetic nanoparticles (NPs) are few other reported techniques for reverse mode PDLCs. HA of LC molecules was also achieved by utilizing the polysulfone polymer and surfactant (ionic and nonionic) in PDLC mixtures. Besides, the encapsulation of monomer molecules in LC droplets to control the orientation of LC directors by photopolymerization of monomer performed in a magnetic or electric field was also employed .…”

Pluronic polymer crosslinked with thio-ene in polymer dispersed liquid crystal films

“…Earlier in the PDLC studies; in order to control the surface anchoring energies, the amphiphilic materials such as the polymers and surfactants were utilized to reduce the surface anchoring interactions. [18][19]22 Norland Optical Adhesive 65 (NOA65) is a well-known commercial material used in PDLCs studies. 23,24 It is composed of thiol-ene molecules containing the SH 2 -group and multifunctional groups, insuring cross-linking and network formation as well as a photo-initiator.…”

“…[25][26][27] Particularly in PDLC studies, NOA65 is utilized as key material to control the rate of phase separation and related electro-optical and morphological characteristics. 19 In comparison of the acrylate-based display devices with the thiol-ene system; the thiol-ene provides various useful features, like less light initiator dosage, excellent thermal insulation, inertia to oxidation, high refractive index, and water resistance. 20 Many researchers in the display field, still considered that there exists an essential gap, which needed to be further explored in terms of the electro optical enhancement of NOA65-E7 composites, even without the chemical modification of polymer mixture.…”