Characterization and photoinduced properties of photo chromic polymers. 1. Polyesterimides with 4-amino 4´-nitro azobenzene moieties

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Ewa Schab-Balcerzak ◽  
Beate Sapich ◽  
Joachim Stumpe ◽  
Anna Sobolewska ◽  
Andrzej Miniewicz
Keyword(s):  
Optical Anisotropy ◽  
Polarized Light ◽  
Ethyl Benzene ◽  
H Nmr ◽  
Azobenzene Group ◽  
Vis Spectroscopy ◽  
Different Types ◽  
Linearly Polarized ◽  
Kinetics Of ◽  
Dsc Thermograms

AbstractNovel photochromic polyesterimides (PEIs) with two different types of azobenzene units as side groups have been synthesized from 2,2’-{4-[(4- nitrophenyl)-azo} phenyl]iminobis(ethyl benzene-1,2-dicarboxylic acid anhydride-4- carboxylate) and diamines: 2,4-diamino-4’-methylazobenzene and 2,4-diamino-4’- (trifluoromethoxy)azobenzene. An analogous polyesterimide with one azobenzene group based on 1,3-phenylendiamine has been prepared to compare with these PEIs. Molecular structural characterization for these polymers has been achieved by FTIR, 1H NMR and UV-Vis spectroscopy. These amorphous polyesterimides are thermally stable up to 260°C as follows from the thermogravimetric analysis (TGA). The glass transition temperatures (Tg) for the resulting polyimides have been determined from DSC thermograms and are in the range of 141-210°C. The irradiation with linearly polarized light of an Ar+ laser results in the induction of optical anisotropy within the initially isotropic films. Light induced optical anisotropy in polymer films has been studied by examining the value of generated dichroism using Ar+ laser (λ = 488 nm) and by holographic polarization grating recording performed at λ = 514.5 nm. The value of photoinduced dichroism is in the range of 0.15-0.26. The induction of dichroism and kinetics of grating inscription have been investigated in relation to the presence of the second type of azobenzene group in the polymer and its substitution.

Properties of Epitaxial ZnO Thin Films for GaN and Related Applications

1998 ◽  
Vol 537 ◽  
Author(s):  
H. Shen ◽  
M. Wraback ◽  
J. Pamulapati ◽  
S. Liang ◽  
C. Gorla ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Anisotropy ◽  
Polarized Light ◽  
Chemical Vapor ◽  
Zno Thin Films ◽  
Organic Chemical ◽  
Zno Films ◽  
Light Modulator ◽  
Cross Sectional ◽  
Linearly Polarized

AbstractIn this paper, we present a detailed study of high quality (110) ZnO films, epitaxially grown on R-plane sapphire substrates by metal-organic chemical vapor deposition (MOCVD). The epitaxial relationships are (1120) ZnO//(0112) Al2O3 and {0001} ZnO//[0111] A12O3 as confirmed by X-ray diffraction (θ-2θ, and φ-scan) and high-resolution cross-sectional transmission electron microscopy (HR-TEM). Low temperature photoluminescence (PL) indicates the ZnO thin films are almost strain free. Optical absorption and reflection measurements with linearly polarized light indicate a strong optical anisotropy. The polarization rotation towards the C-axis associated with the optical anisotropy is utilized to demonstrate an optically addressed ultra-fast, ultraviolet light modulator.

Preparation of Oriented Nanofilms of Oligo(Phenylimines) Synthesized by Mechanochemistry for Optoelectronic Devices

2011 ◽  
Vol 691 ◽  
pp. 83-91 ◽  
Author(s):  
V.H. Flores Sánchez ◽  
R.A. Vázquez García ◽  
O. Coreño Alonso ◽  
J. Coreño Alonso ◽  
Ma.I. Reyes Valderrama ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Light Emission ◽  
Condensation Reaction ◽  
Polarized Light ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Oriented Films ◽  
Quartz Substrates

Oligo(phenylimines) hereafter named PI6, PI8 and PI9 were synthesized by condensation reaction between the terephtalaldehyde and diamines of different length size (diaminohexane, diaminooctane and diaminononane) via mechanochemistry. The reactions were carried out without solvent or catalyst and completed after only 90 minutes. The products were characterized by 1H-NMR, UV-Vis, FT-IR spectroscopy, GPC, DSC and Small angle X-ray diffraction. Thin films were prepared by spin coating from concentrated solutions on glass and quartz substrates and mechanically rubbed with a polyacrylonitrile tissue. The oriented films were studied by both Laser Scanning Confocal Microscopy (LSCM) and UV-Vis spectroscopy. With this last technique, the higher optical dichroism was observed for PI6. The oriented films of this oligo(phenylimine) were thus used as patterns to induce molecular orientation of a fluorescent phenyleneethynylene polymer in order to obtain polarized light emission.

Nematic Liquid Crystals (NLC) Alignment by the Oriented Nanopatterns of some Polymers Functionalized with Monochlorotriazinyl-β-Cyclodextrin

2012 ◽  
Vol 20 ◽  
pp. 117-128
Author(s):  
Ana Maria Grigoriu ◽  
Constantin Luca ◽  
Aurelia Grigoriu ◽  
Cristina Racu ◽  
Gabriela Hitruc ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Uv Light ◽  
Nematic Liquid Crystals ◽  
Polarized Light ◽  
Hydroxyl Groups ◽  
Nanostructured Surfaces ◽  
Dichroic Dye ◽  
Vis Spectroscopy ◽  
Linearly Polarized ◽  
Ft Ir

This paper presents the practical strategies of obtaining the oriented nanostructured surfaces of some polymers functionalized with monochlorotriazinyl-β-cyclodextrin (MCT-β-CD) by two techniques: uniaxial rubbing or linearly polarized UV light (LPUVL) irradiation. We have chosen for the present study polymers and copolymers with exotic behavior with hydroxyl groups allowing the grafting of the reactive product monochlorotriazinyl-β-cyclodextrin or whose pyridinic nuclei can be complexated with MCT-β-CD. The obtained oriented nanostructures align colourless nematic liquid crystals (NLC) or NLC coloured with a dichroic dye. The orientation of NLC has been studied by means of polarized light FT-IR spectroscopy (IR dichroism) and polarized light UV-VIS spectroscopy (VIS dichroism). The initial polymers as well as the chemically modified products have an exotic behavior with regard to the ability of orientating the NLC. The polymers functionalized with MCT-β-CD orientate the NLC perpendicularly to the rubbing direction (or, for photopolymers, perpendicularly to the electrical vector of LPUVL).

UNPOLAR AND POLAR HOLOGRAPHIC GRATING RECORDING BY CIRCULARLY POLARIZED LIGHT ON PHOTOANISOTROPIC AZOBENZENE LANGMUIR–BLODGETT FILMS

2003 ◽  
Vol 12 (04) ◽  
pp. 495-511 ◽  
Author(s):  
L. M. BLINOV ◽  
R. BARBERI ◽  
F. CIUCHI ◽  
M. P. DE SANTO ◽  
G. CIPPARRONE ◽  
...  
Keyword(s):  
Probe Beam ◽  
Optical Anisotropy ◽  
Polarized Light ◽  
Spatial Modulation ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Langmuir Blodgett ◽  
Linearly Polarized ◽  
Langmuir Blodgett Films ◽  
Ion Laser

A comparative study of photo-induced optical anisotropy was carried out on Langmuir–Blodgett films prepared from five different amphiphilic azobenzene derivatives. The anisotropy was induced by a linearly polarized pump beam of an Ar-ion laser at λ=514 nm and monitored by a linearly polarized probe beam of a He–Ne laser at λ=633 nm . Large optical anisotropy up to 0.35 has been induced. Holographic gratings were recorded by two left circularly polarized beams of the Ar-ion laser and time evolution of the first-order diffraction efficiency of the probe beam was recorded in an automatic regime. In such a geometry, the spatial modulation of refraction index reaches 0.14. The experimental data is consistent with a model for a photo-induced collective chromophore realignment in the heterogeneous domain structure of the films studied. The influence of an electric field of the corona discharge on the grating recording process was also studied and polar diffraction gratings have been prepared by a spatially periodic photo-poling process.

scholarly journals Linearly Polarized UV Light-Induced Optical Anisotropy of PVA Films and Flexible Macrocycle Schiff Base Ni(II), Cu(II), Zn(II) Dinuclear Complexes

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 760
Author(s):  
Masahiro Takase ◽  
Shiomi Yagi ◽  
Tomoyuki Haraguchi ◽  
Shabana Noor ◽  
Takashiro Akitsu
Keyword(s):  
Optical Anisotropy ◽  
Molecular Orientation ◽  
Soft Matter ◽  
Uv Light ◽  
Polarized Light ◽  
X Ray ◽  
Crystallographic Symmetry ◽  
Linearly Polarized ◽  
Dinuclear Metal Complexes ◽  
Crystal Structural

Three dinuclear metal complexes (comprised of six-coordinated nNi2L and five-coordinated nCu2L and nZn2L) were confirmed by means of elemental analysis, UV-vis and IR spectra, and single X-ray crystal structural analysis in a spectroscopic study. The stable structures of these nNi2L, nCu2L, and nZn2L complexes in poly(vinylalcohol) (PVA) films were analyzed using UV-vis spectra. The molecular orientation of hybrid PVA film materials after linearly polarized light irradiation was analyzed to obtain the polarized spectra and dichroic ratio. Among the three materials, nNi2L and nZn2L complexes indicated an increasing optical anisotropy that depended on the flexibility of the complexes. We have included a discussion on the formation of the pseudo-crystallographic symmetry of the components in a soft matter (PVA films).

scholarly journals THE EFFECT OF THE SUBSTITUENT NATURE IN THE AZOBENZENE CHROMOPHORES ON DIFFRACTION EFFICIENCY OF POLARIZATION HOLOGRAMS

2019 ◽  
pp. 30-33
Author(s):  
M. Davidenko ◽  
I. Davidenko ◽  
V. Kravchenko ◽  
O. Mokrinska ◽  
V. Pavlov ◽  
...  
Keyword(s):  
Diffraction Efficiency ◽  
Optical Anisotropy ◽  
Polarized Light ◽  
Mutual Orientation ◽  
Polarization Holography ◽  
Light Modulators ◽  
Linearly Polarized ◽  
Light Beams ◽  
Plane Wave Front ◽  
Azobenzene Groups

The films of polymeric composites containing monomers of azobenzene dyes or azobenzene lateral groups chemically bonded to the main polymer chain demonstrate photoactive properties, and can be used in electrooptical light modulators and in recording media (RM) for polarization holography. Photoinduced optical anisotropy (PIA) appears under influence of linearly polarized light caused by the processes of trans-cis-izomerization of the azobenzene groups. This process is determining for application of the considered materials as RM for polarization holography. The films of polymeric polarization sensitive media based on a copolymer of styrene with nonyl methacrylate doped with azobenzene-type dyes with different electron-acceptor substituents are obtained in this work. In the films of copolymer the holograms of the plane wave front were registered for parallel and orthogonal orientations of polarization vectors of the object and reference light beams. Their photoelectrophysical, in particular photodielectric, and information properties are investigated. It was established, that when the mutual orientation of the recording beams changes from the orthogonal to parallel orientation the diffraction efficiency of the holograms increases in the case of using azo dye with the maximum number of auxochromic substituents in the molecule. The effect of the diffraction efficiency dependence on the chromophores structure is connected with the deepening of dye color. The photo-induced optical anisotropy in the films appears due to a change of the concentration ratio of trans- and cis-isomers of azobenzene dye fragments. This conclusion is confirmed by the photodielectric measurements data, namely, by the negative sign of the photodielectric effect, observed experimentally in the investigated thin film structures. It was shown, that investigated compositions can be used as information media for polarization holography.

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

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