V. I. Zolotarevskii

Fine structure of polymeric compositions based on latexes modified by water-soluble phthalocyanine

The data of the atomic force microscopy of films and coatings based on the water-soluble polymer binders modified with water-dispersion phthalocyanine (WDP) are considered. In the formation of films from a latex polymer with a low glass-transition point (−17°C) and both nonmodified and phthalocyanine-modified latex particles completely coalesce, which manifests in the high smoothness of the surface and the WDP distribution over the whole volume of the polymer. The surface roughness of an elastic polymer with a glass-transition point below 25°C is observed in the case of polyalkyl (meth)acrylate films that contain WDP. Here, a continuous network of latex particles that contact each other is clearly seen. This type of structure appears at a dispersion-phase WDP concentration of up to 10−3 to 10−2 mol/l when the fluoride is homogeneously distributed in the latex polymer. During the film formation, WDP is localized on the particle surfaces due to the interaction between its amine groups and carboxyl groups of the polymer surface.

Transformation of metal-oxide nanostructures in the process of afteroxidation of iron reactively evaporated in oxygen atmosphere

The methods of atomic force microscopy combined with the digital processing of images were used to study the change in the morphology of nanostructured metal-oxide coatings obtained by reactive evaporation at 10−6 torr in the atmosphere of oxygen and further low-temperature iron afteroxidation in an air atmosphere at different temperatures. It is shown that a nanostructured layer with a unimodal distribution according to the size and degree of nonsphericity of the particle is formed in the case of sputtering. Using the sample detection methods, it is shown that a unimodal distribution is transformed into a bimodal distribution at an increase in the reoxidation temperature from 50 to 200°C, after which it becomes a trimodal distribution, which proves that the building blocks of a nanostructured layer are nanoparticles and four- and 16-particle surface nanoparticle conglomerates. This structure can explain the functional properties of these coatings, which are of practical importance.

On the electrocontact oxidation of vacuum iron nanocondensates: II. Structural characteristics

Changes in the composition and morphology of thin-film conductors based on a nanostructured metal-oxide nanocomposite, which was obtained by the vacuum deposition of iron in an oxygen atmosphere at 10−5–10−3 mmHg on an amorphous glass substrate, induced by external electric current are studied using atomic force microscopy and Raman spectroscopy. The most pronounced zone of degradation is observed in the middle part of the conductor. Compared to the undistorted parts of the conductor, the degradation zone is characterized by an increased content of magnetite phase, which is formed as a result of the prevailing further oxidation of nanoparticles constituting the film. The surface morphology of the degraded part is characterized by the appearance of extended structures, some of which are nanoparticles and submicroparticles oriented in the direction of the applied electric current, which can be due to both the electric mass transfer of the metal and its electric oxidation. The other kind of extended structures are nanofibers composed of adjoining and coalesced metal-oxide nanoparticles, which can appear due to the electric oxidation in the electric contact areas between nanograins and leads to the coalescence of the neighboring nanograin chains into nanofibers. It is proposed that the electrocontact oxidation should be used as a method of creating fibrous metal-oxide nanocomposites based on vacuum deposits of iron or other metals.

Nonlinear optical properties of systems based on (tetra-15-crown-5-phthalocyaninato)indium(III)

The nonlinear optical properties of solutions of (2,3,9,10,16,17,23,24-tetra-15-crown-5-phthalocyaninato)indium(III) [(15C5)4Pc]In(OH) in tetrachloroethane (TCE) have been studied by the z-scan method. It has been found that a nonlinear optical response is due to supramolecular associates formed in a tetrachloroethane solution by heating to 90°C/slow cooling to room temperature cycling. The formation of the supramolecular associates has been studied by atomic force microscopy (AFM) and electronic absorption spectroscopy (EAS). It has been shown that a single thermal treatment of [(15C5)4Pc]In(OH) solutions in TCE results in the predominant formation of dimers, as evidenced by both a short-wavelength shift of the Q-absorption band of the monomeric complex (λmax = 692 nm) to the band of λmax = 653 nm and height doubling of molecular entities as measured by AFM. The dimers are responsible for the two-photon absorption measured in the femtosecond range, which has a relatively high cross section of σ2 = 1.38 × 10−46 cm4 s/(molecule, photon) or 1.38 × 104 GM. According to the AFM data, three cycles of heat treatment of the solution leads to the formation of supramolecular assemblies of about 200 nm length. The optical spectrum exhibits long-wavelength absorption at λmax = 841 nm and the long-wavelength edge near 1300 nm. In the case of nanosecond 1064-nm laser irradiation, the linear absorption S0 → S1 is primary, having the cross section of σ0 = α0/N = 2.3 × 10−20 cm2. The known high quantum yield (close to unity) of triplet states of indium phthalocyanines suggests that the main nonlinear optical effect is determined by intersystem crossing S1 → T1 and triplet-triplet absorption T1 → T2. The absorption cross section is σT-T = 1.14 × 10−19 cm2.

Third-order optical susceptibility of single-walled carbon nanotubes

The third-order susceptibility of tetrachloroethane dispersions of capped single-wall carbon nanotubes (SWCNT) has been analyzed by the z-scan technique using a femtosecond laser, and the SWCNT image obtained by atomic force microscopy has been also presented.

Influence of Heavy Central Atom on Photoelectric, Nonlinear Optical, and Photorefractive Properties of Metal Phthalocyanines

Measurement of the photoelectric and photorefractive characteristics of 2,3,9,10,16,17,23,24-tetra(15-crown-5)phthalocyaninatoacetatoyttrium(III) [(15C5)4Pc]Y(OAc) has made it possible to reliably establish the features of decrease in the quantum yield of generation of charge carriers φ0 and photorefractive two-beam coupling gain Γ with an increase in the atomic weight of the central metal in a series of related gallium(III), yttrium(III), ruthenium(II), and indium (III) phthalocyaninates. These features can be due to an increase in the spin-orbit interaction constant with increasing atomic weight of the central metal, a change that leads to an increase in both the contribution of triplet excited associates to the formation of mobile charge carriers and the rate of the reverse reaction T1 → S0, which effectively inhibits the formation of charge carriers through the excited triplet state. The measurement of photoelectric and photorefractive characteristics at 1064 nm has shown that the quantum yield of electron-hole pairs in the composite polyvinylcarbazole/supramolecular assemblies of yttrium complex is φ0 = 0.6 and the two-beam coupling gain coefficient Γ is about 35 cm−1 at E0 = 120 V/μm. The dielectric susceptibility measured by the z-scan technique in a solution of the yttrium complex in tetrachloroethane (1 mg in 1 mL) is χ(3) = 4.2 × 10−10 esu.

Relaxation behavior of latex-polymers in frost-resistant aqueous-dispersion deep-penetration ground coats modified by water-soluble dye

The effect of a water-soluble indanthrene blue dye on the relaxation structure of styrene–acryl latex polymer with the glass-transition point below 5°C is studied in a frost-resistant aqueous-dispersion coat using the method of dynamic mechanical-relaxation spectroscopy. A significant difference is found between the change in the intensity of the maximum of α-relaxation dissipative losses of a latex-polymer binder in the ground coat and in free latex polymer when they are modified by a blue dye, which is due to the ground-coat composition. Special attention is paid to relaxation effects in the negative temperature range.

On electrocontact oxidation of iron nanocondensates

The transformation (under the effect of current passed) of a nanostructured metal-oxide coating produced by vacuum deposition of iron in an oxygen atmosphere at a pressure of 10−4 mm Hg on an amorphous glass substrate is studied by measuring voltammetric characteristics. In the freshly deposited film, a linear characteristic is observed that may correspond to direct quantum mechanical tunneling in thin oxide interlayers between metal nanograins. With an increase in the applied current density, when a certain threshold is reached, the conductivity of the conductor rapidly drops because of the thermo- and electrooxidation. In a degraded conductor at a prethreshold current density, a nonlinear voltammetric characteristic is observed, which may be related to the change in the mechanism of current flow restricted by the volume charge, as well as to the negative temperature resistance coefficient typical of fine-crystalline granular nanocomposites.

The influence of a solvent on the aggregation of ruthenium(II) tetra-15-crown-5-phthalocyaninate

The images of ensembles of ruthenium(II) complexes with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules, (R4Pc)Ru(TED)2, obtained on an atomic force microscope were analyzed. A comparison with the X-ray structure analysis data was performed to estimate the number and mutual arrangement (architecture) of molecules in supramolecular aggregates depending on the nature of the solvent and the temperature of solutions before casting. Storage at room temperature or heating of a solution of the complex in tetrachloroethane caused the formation of stable supramolecular “wires” 600 nm or more long. The z-scanning method was used to study the third-order nonlinear optical characteristics of solutions of the (R4Pc)Ru(TED)2 complex in tetrachloroethane.

Relaxation Behavior of a Styrene–Acryl Latex Polymer in the Freezing–Thawing Regime

Relaxation behavior of a styrene–acryl latex polymer with a vitrification temperature of ≤5°С is analyzed using the method of dynamic mechanic-relaxation spectroscopy and atomic-force microscopy for its further use in frost-resistant compositions as a polymer binder. The change in the intensity of maximum of dissipative losses of α-relaxation and the μ-process is found in polymer films in the negative temperature range as dependent on the duration and number of their preliminary freezing–thawing cycles at–30°С, which indicates a change in the polymer-relaxation structure confirmed by the values of Young’s modulus and modulus defect.