Articles written in Bulletin of Materials Science
Volume 29 Issue 6 November 2006 pp 599-603
Morphological control and polarization switching in polymer dispersed liquid crystal materials and devices
K K Raina Pankaj Kumar Praveen Malik
Liquid crystals dispersed in polymer systems constitute novel class of optical materials. The precise control of the liquid crystal droplet morphology in the polymer matrix is essentially required to meet the prerequisites of display device. Experiments have been carried out to investigate and identify the material properties and processing conditions required for the precise control of the droplet morphology of the dispersed liquid crystal systems. Polarization switching has been studied. Aligned liquid crystal dispersed systems showed higher polarization over unaligned ones.
Volume 42 Issue 5 October 2019 Article ID 0215
Improvement in electro-optical and dielectric characteristics of ZnO nanoparticles dispersed in a nematic liquid crystal mixture
AMIT SHARMA PRAVEEN MALIK RAVINDRA DHAR PANKAJ KUMAR
Reported herein is the effect of dispersion of a ﬁxed amount of 0.5% (wt/wt) ZnO nanoparticles (NPs) in a nematic (E7) liquid crystal (LC) mixture. Dispersion of ZnO NPs results in a signiﬁcant improvement in electro-optical and dielectric parameters of the nematic mixture. Comparative analysis of undoped and NP-dispersed samples shows a reduced threshold voltage with better transmittance without compromising dielectric permittivity characteristics. In addition, an increase in the contrast ratio, birefringence, alternating-current conductivity and band gap was observed after dispersion of ZnO NPs in LCs. A polarized optical microscopic study of the NP-dispersed sample substantiates a slight increase in nematic–isotropic phase transition temperature of LCs.
Volume 45 All articles Published: 16 May 2022 Article ID 0085
Interdependency among electro-optic characteristics and absorption coefficient of homeotropically aligned liquid crystal considering Beer’s law theory
CHINKY PANKAJ KUMAR ANKIT RAI DOGRA PRAVEEN MALIK
In the present study, interdependency among electro-optic (E-O) characteristics and absorption coefficient of homeotropically aligned liquid crystal (HALC) considering Beer’s law theory has been studied. Specifically, HALC cellswere prepared using uniform dispersion of ZnO nanoparticles into the nematic liquid crystal without applying any surface treatment to the substrates. Then azo dichroic dye (orange) was added in a fixed concentration to the prepared nanoparticles dispersed LC mixture. The morphological and absorption characteristics of prepared HALC cells were found to be improved with the addition of azo dichroic dye. The optical textures observed at macroscopic and microscopic levels are in correspondence with each other and showed excellent OFF/ON switching with magnificently dark and bright views. Moreover, HALC cells doped with azo dichroic dye exhibited a higher value of absorption coefficient with an improved contrast ratio. Thus, a good consistency was observed among experimentally observed E-O characteristics and theoretically measured absorption coefficient.
Volume 46, 2023
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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