Poly(vinylidenefluoride) film (PVDF) doped with Eu(III)(NO3)3(o-Phenanthroline)2 complex (complex A) was manufactured using an extrusion technique. Emission spectrum of the film was compared to spectra of the dopant and polyethylene based film. Stretching the film resulted in a sharp growth of intensity and reshaping of the luminescence spectrum. The impact of the PVDF matrix on the photoluminescence spectra of complex A is attributed to the Stark effect. Reasons for the increase of luminescence intensity are discussed. Quantum chemical calculations revealed a marked longwave shift of the lowest triplet and singlet energy levels of complex A compared to free phenanthroline. The amplification and frequency shifting of the luminescent spectrum of europium-complex-doped PVDF may lead to promising applications.
The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene-based film and polypropylene-based rod both doped with these complexes were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)-thenoyltrifluoroacetone-1,10-phenanthroline complex (Eu(III)) and Eu(III)-La(III)-1,10-phenanthroline complex (Eu(III)-La(III)). Comparison was made between these samples regarding absorption, excitation, emission and a lifetime of luminescence. Dependence of emission intensity on the excitation energy was determined. Emission spectra of the films were studied at room and helium temperatures. Optical properties of Eu(III) samples are different from Eu(III)-La(III) samples. Significant difference in spectra of these two types of samples may be attributed to the La(III) action.
Roman Pogreb, Binyamin Finkelshtein, Yuri Shmukler, Albina Musina, Oleg Stanevsky, Shlomo Yitzchaik, Alexander Gladkikh, Alexander Shulzinger, Vladimir Streltsov, Edward Bormashenko
Light-converting polyethylene film containing Eu(III) complex with phenanthroline was manufactured under an extrusion process. The film was characterized by means of time-of-flight secondary-ion-mass spectrometry (TOF-SIMS), ultraviolet-visible-infrared (UV-Vis-IR) spectroscopy, study of excitation and luminescence spectra, quantum yield and lifetime of luminescence. TOF-SIMS surface mapping showed the uniform distribution of Eu(III) over the film. Typical Eu(III)-phenanthroline complex excitation and fluorescence spectra were recorded, the quantum yield of fluorescence being 5±2%. Luminescence lifetime was measured as 0.4 ms. Visualization of strong subpicosecond UV laser beams through the use of developed film has been demonstrated.
The use of polyaniline emeraldine base films as antireflection coating for near and middle IR optics elements was studied. The optical quality of ZnSe substrates spin-coated with thin PANI EB layers were studied using a Linnik interferometer. The spectral properties of PANI coated ZnSe plates were investigated in broad IR band with FTIR spectrometer. It was shown that PANI coating allows a significant decrease of Fresnel losses in the near and middle IR bands (1.0-6.25 μm). The coating allowed continuous transmission of high power density of IR radiation produced by CO2 laser. The transmission coefficient doesn't depend on the incident laser beam power density (up to 3 W/mm2). The laser irradiation damage threshodl of the PNAI EB coating was studied at a wavelength of 1.5 μm and established as high as 0.1 GW/mm2 (τ=12 10-9s) for PANI EB coating wtih a thickness of 150 nm. Microhardness of the PANI EB coated ZnSe plates was established as satisfactory.
Mechanical properties of glassy selenium and selenium based IR chalcogenide glasses Se55As45, Se67.5As20Ge12.5 and Se57I20As18Te3Sb2 were first studied using dynamical mechanical analysis (DMA). DMA method gave the valuable information about complex Young's modulus of the glassy materials. In parallel with the study of mechanical properties of pure Se and Se-based IR glasses there also has been cleared the character of the glass transition process. The results of DMA study were compared with data obtained by differential calorimetry. The glass transition temperature, established by calorimetric measurements is lower than the temperature, which corresponds to peaks of the loss tangent for all kinds of materials under study. Activation energies of relaxation processes in IR chalogenide glasses were calculated using DMA data.
This work presents the novel composite material based on a polymer (LDPE) and metal alloy, which have a close melting point. The process of blending the main components of the composite was developed using the extrusion mixing. The process of extrusion of composite films with a thickness 50- 300 micrometers was worked out using an extruder equipped with a cast film die. This process allowed production of the binary composite, with up to 15 wt. % of the alloy dispersed uniformly in the polymer matrix. It was shown that carbon black is highly compatible with the basic components and could be dispensed uniformly in the obtained films. The structure of the composite films was studied with a scanning electron microscope. Physical properties of the binary and ternary composites were investigated, including conductivity and temperature dependence of the thermal capacity. Non- ohmic behavior of the ternary composites was revealed. The IR spectra of the composites were studied using an FTIR spectrophotometer. It was shown that processing polyethylen in the presence of a low-melting-point alloy causes changes in the structure of polyethylene. The presence of alloy caused intensive oxidation of carbon black in the ternary composite as well.
Fiberoptic Evanescent Wave Infrared Spectroscopy facilitates measurements on samples in situ and in real time. This will be used for the analysis of chemical processes, for monitoring of pollutants in water or in soil and for diagnosis of diseases
The presented work demonstrates that powerful laser radiation causes changes in absorbance spectra of epoxy resin and polyethylene. Thin polymer films were located between infrared AgBrCl optical fibers and exposed to the radiation of CO2 laser. The outpot of the laser source has been varied in the range 0-8.5 Wt. Absorbance spectra were measured by FTIR spectrophotometer. It was revealed that characteristic absorbance peaks of polymers decay under the powerful IR light. The apparent dependence of peak magnitude on IR radiation power has been established. The mathematical theory of the observed effect was worked out. Authors suggested that the effect under discussion is caused by oxygen-free thermal action of IR radiation on the chemical structure of polymer materials. The revealed effect could be effectively used for the lowering of losses in adhesive contacts of IR optic elements. The novelty of the proposed method lies in the fact that thermal treatment is localized strictly in adhesive contact, optical elements to be contacted (fibers, lenses, etc.) which are highly transparent in IR don't experience the IR radiation, but polymer adhesive is subjected to a temperature rise.
This work presents the new approach to the investigation of mass transport process in polymers. The Fiber Optic Evanescent Wave Spectroscopy has been used for the real time investigation of diffusion processes in glassy polymers. Unclad AgClBr fibers of 0.9 mm diameter were dip coated by polystyrene layers of 1 - 30 micrometers thickness. The transmission of the fibers in the mid-IR was measured using a Fourier Transform Infrared spectrometer. The penetration of liquids into these layers gave rise to significant changes in the measured spectrum. These changes were used for diffusion studies in situ. The mathematical model, which allows realizing the quantitative treatment of experimental data, was developed. The model details with processes which take place at two interfaces: polymer/liquid and polymer/optical fiber. It was established that the initial stage of diffusion is of the strictly Fickian character. The model permitted us to calculate the coefficient of diffusion of water in polystyrene with a high accuracy. The huge amount of experimental points, which could be obtained by our method, allows calculation of the equilibrium concentration of penetrating liquid with an extremely high precision. This advantage of FEWS procedure offers a high accuracy of calculations of parameters of diffusion. It must be emphasized that the thickness of the film that could be defined with the least precision doesn't affect on final results. The final stage of diffusion is non-Fickian.
The novel composite material based on middle density polyethylene on one hand and thermoplastic chalcogenide glass on other hand has been worked out. Both materials used in the research are highly transparent in the middle and far IR but refraction indexes of components differ dramatically. The basic materials, polymer and glass, have close viscosities at the temperature of polyethylene processing. This fact allowed use of the extrusion technique for homogenization purposes. We proved, that the controlled structure of a composite could be derived through the varying of technological parameters of the mixing process. Single- and twin screw extrusion processes obtained compositions, which contain up to 50% particles of chalcogenide glass, which were dispersed in the polymer matrix. The highly homogeneous compositions that contain perfect spherical glass particles of 1-2 micrometers in diameter dispersed into polymer matrix were obtained as well. Highly oriented structures involving chalcogenide glass fibers immersed in the polymer matrix were prepared under high stretch speeds as well. Such fiberlike structures exhibited pronounced polarization properties. We studied the optical properties of the composite and came to the conclusion that the controlled structure of the composite allows variation in its optical properties. It was established that it is possible to produce a composite that is opaque in the visible and near IR, and highly transparent in the 2-25-micrometers wave length band. Light scattering on oriented and disordered structures was studied by the IR spectro-goniometer. The novel composite which was developed by our group is intended for various IR-optics applications.
Infrared spectral analysis of human blood serum was carried out using FTIR-FEWS (Fourier Transform Infrared Fiberoptic Evanescent Wave Spectroscopy). The fiberoptic sensor elements were short (10.5 cm) lengths of unclad AgClBr fibers of diameter 0.9 mm. In order to protect the fibers from interaction with the blood serum we developed a dip coating technique, which made it possible to control the coating thickness. Three polymer materials were tested: polysulfone, polystyrene and room temperature vulcanized silicone elastomer. It was found that layers of thickness 2 - 3 micrometer provide chemical protection, while making it possible to carry out FEWS measurements. The measured spectra were analyzed by neural network analysis, to predict the concentrations of urea, uric acid, cholesterol, total protein and cretonne. The predicted concentrations were compared with the results obtained using standard chemical analysis of the blood (SMAC) and good correlation was observed, with errors of only few percent.
Silver halide IR-transmitting fibers were coated with polymer films in order to protect them from deterioration caused by interaction with biological fluids. Such coated fibers can be used for human blood serum analysis carried out the fiberoptic evanescent wave spectroscopy (FEWS) using a Fourier transform infrared spectrometer. A dip-coating procedure was worked out for coating fibers with polystyrene or silicone-elastomer thin films. Deterioration tests of coated fibers in saline solution which imitates human blood serum salts were performed. These demonstrated that the polymer layers provide protection to the fibers, while making it possible to carry out FEWS measurements.
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