Siyamak Shahab

Anisotropy of polarizing polyvinyl alcohol films

The anisotropy ofthe polarizing films produced on the base of polyvinyl alcohol and dichroic dyes has been studied by visible dichroism and heat conductivity anisotropy methods. The influence ofstructure and content ofthe dye as well the stretch ratio of films on the orientation factors has been investigated. The comparative results allowed to evaluate a degree of arrangement of polymer chains and dye molecules in anisotropic films.

Broad band thermostable polarizing film based on poly (vinyl alcohol), a quinoline derivative and ZnO nanoparticles

In the present study, for the first time on the basis of polyvinyl alcohol (PVA), dichroic dyes: (sodium 4-[(4E)-4-[(2E)-2-(2-chloro-3-{(E)-2-[1-(4-sulfonatobutyl)quinolinium-4-yl]ethenyl}-2,3-dihydro-1H-inden-1-ylidene)ethylidene]quinolin-1(4H)-yl]butane-1-sulfonate) (I), 6-amino-4-hydroxy-3-((4-(phenyldiazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid (II), and Chicago Sky Blue (III) broad band thermostable polarizing PVA-films were created. The obtained polarizing PVA-films had polarizing efficiencies (PEs) in the range of 97–99% in UV-Vis (300–695 nm) and PEs of 90–96% in the near IR (819–855 nm) regions of the spectrum. The photostability of the films could be improved by ZnO nanoparticles (average length ∼ 1 μm and diameter ∼ 85 nm) incorporated in a polymer matrix. Apparently, ZnO NPs act as a stabilizer in the photochemical process of dye degradation. During the study, it was established that oriented broad band PVA-films are a phenomenon of the anisotropy of thermal conductivity (λ‖/λ⊥). This is very important for the existence of thermostable polarizing PVA-films. It was also found that in the films the thermal conductivity in the direction of orientation (λ‖) was higher than in a direction perpendicular to the orientation (λ⊥).

Anisotropy (optical, electrical and thermal conductivity) in thin polarizing films for UV/Vis regions of spectrum: Experimental and theoretical investigations

In the present work, the quantum theoretical calculations of the molecular structures of the three newly synthesized azomethine dyes: have been predicted using Density Functional Theory (DFT) in solvent dimethylformamide (DMF). The geometries of the azomethine dyes were optimized using the PBE1PBE/6-31+G level of the theory. In addition, the electronic spectra of these compounds in solvent DMF were carried out using the TDPBE1PBE, TDPBEPBE, TDB3LYP methods with 6-31G, 6-31+G, 6-31+G*, 6-31++G* basis sets. After quantum-chemical calculations three new azomethine dyes for optoelectronic applications were synthesized. Based on polyvinyl alcohol (PVA) and the new synthesized azomethine dyes polarizing films for UV/Vis regions of the spectrum were developed. The main optical parameters of polarizing PVA-films (Transmittance and Polarization Efficiency) have been measured and discussed. Anisotropy of electrical and thermal conductivity of the PVA-films has been investigated.

IR-polarizing film containing a new quinoline dye and Fe3O4 nanoparticles: optical and thermophysical investigations

In the present work, the structure and some molecular properties of a new substance, monosodium mono(4-(2-(2-(2-chloro-1-(2-(1-(4-sulfonatobutyl)-3,4-dihydroquinolin-2(1H)-ylidene)ethyliden)-1H-inden-3-yl)vinyl)-3,4-dihydroquinolin-1(2H)-yl)butane-1-sulfonate (M), with a strong maximum absorption in the near IR region (λmax = 764 nm) of the spectrum, was modeled using the Density Functional Theory method (DFT/B3LYP/6-311++G*) and then synthesized. The calculated electronic absorption spectrum of M in dimethylformamide (DMF) by TDB3LYP/6-311++G* method and the experimental spectra of M in DMF and in aqueous medium are presented. The charge delocalization of M has been performed with the help of natural bond orbital (NBO) analysis. The UV, IR, and 1H NMR spectra of M are presented. On the basis of poly(vinyl alcohol) (PVA), a thermostable polarizer film was developed incorporating the new synthesized dye M and magnetite (Fe3O4) nanoparticles (NPs) absorbing in the near IR region of the spectrum (λmax = 750–812 nm) and with polarization efficiency (PE = 95%) in the absorption maximum. The main spectral polarization parameters (transmittance and optical density) of the stretched colored PVA films with M and M + Fe3O4 NPs were measured and discussed. Oriented colored PVA films having the phenomenon of anisotropy of thermal conductivity (λ∥/λ⊥) were established. Thermal conductivity in the direction of orientation (λ∥) is higher than that in the direction of perpendicular orientation (λ⊥). The developed thermostable IR-polarizer film may be used in laser technologies, polarizing microscopes, circular polarizers, magnetometers, spectropolarimeters and electrical signal sensors.

Chemical and optical investigations of film polarizers with azodyes

Light-polarizing films are a basis of sheet polarizers, which are used in liquid crystal systems. A light-polarizing film is generally produced by the formation of a uniaxial stretched film made of polyvinyl alcohol (PVA) or its derivatives containing a light-polarizing element like iodine or dichroic dye. Films with iodine are excellent in their initial polarizing performance but poor in resistance to moisture and heat. In order to improve the durability of polarizers more stable dichroic element are used instead of iodine. Films with dichroic organic dyes first of all azodyes are superior in the resistance to moisture and heat as compared with iodine systems. Searching for thermally stable dyes, which do not change their colour under of the influence of high temperature and humidity and are suitable for the manufacturing of effective polarizers is an actual problem. In this paper we show the results of optical investigations of uniaxial PVA-films with iodine (with and without transparent layer) and dichroic azodye.

Spectroscopic Studies (Geometry Optimization, E → Z Isomerization, UV/Vis, Excited States, FT-IR, HOMO-LUMO, FMO, MEP, NBO, Polarization) and Anisotropy of Thermal and Electrical Conductivity of New Azomethine Dyes in Stretched Polymer Matrix

AbstractIn the present work, first time the molecular structures of three newly synthesized azomethine dyes: (1Z)-N-benzylidene-4-((E)-1-(oxim)ethyl)benzenamine (AAFOX-1), 4-((1Z)-(4-((E)-1-(oxim)ethyl)phenylimino)methyl)phenol (AAFOX-7), (Z)-1-(4-((Z)-(4-methoxybenzylidene)amino)phenyl)ethanone oxime (AAFOX-8) have been investigated using Density Functional Theory (DFT) in dimethylformamide (DMF). The electronic spectra of azomethine dyes in a DMF solvent was carried out by TD-DFT method. After quantum-chemical calculations three new azomethine dyes for optoelectronic applications were synthesized. FT-IR spectra of the title compounds are recorded and discussed. The computed absorption spectral data of the azomethine dyes are in good agreement with the experimental data, thus allowing an assignment of the UV spectra. The molecular HOMO-LUMO, excitation energies and oscillator strengths for E and Z isomers of the dyes have also been calculated and presented. Optical Properties of the PVA-films containing new substances have been also investigated. Polarizing Efficiency (PE) of obtained PVA-film is 70–80 % at Stretching Degree (Rs) 3.5. First time anisotropy of thermal and electrical conductivity of PVA-films containing E and Z isomers of the dyes was also measured and discussed. It is new result for physical chemistry of organic dyes. Graphical AbstractWe studied anisotropy of thermal and electrical conductivity of new azomethine dyes in stretched polymer matrix and electronic properties of new azomethines have been also investigated using Density Functional Theory (DFT) in dimethylformamide (DMF).

Adsorption Properties of the New Anti-Cancer Drug Alectinib on CNT(6,6-6) Nanotube: Geometry Optimization, Molecular Structure, Spectroscopic (NMR, UV/Vis, Excited State), FMO, MEP and HOMO–LUMO Investigations

In the present work, the non-bonding interaction of the new drug Alectinib and the CNT(6,6-6) nanotube has been studied at the B3LYP/6-31G* level of theory. Results have shown that the electronic properties, chemical shift tensors, and natural charges are sensitive to the adsorption on the CNT(6,6-6) nanotube. Furthermore, we studied the electronic spectra of the Alectinib and the complex CNT(6,6-6)/Alectinib by time dependent DFT (TD-DFT) method for investigation of the maximum wavelength value of the Alectinib before and after the non-bonded interaction with the CNT(6,6-6) nanotube. It was found that the adsorption of the compound Alectinib over the CNT(6,6-6) changed the value λmax as bathochromic shift.

Film transflect polarizer

The results of development of technology for producing film polarizers of light transmitting/reflecting type are disclosed, these film polarizers are design used in liquid crystal display devices (LCD). Light reflecting composition with given optical properties has been developed, the composition was used to form a covering on light transmitting polarizer. The covering is mechanically protected by poly(ethylterephthalate) film which is removed after film polarizer is glued to LCD.