Scanning Tunneling Microscopic and Scanning Tunneling Spectroscopic Studies of Nanostructure and Surface Energy Properties of Stainless Steel Kh18N10T. 1. Measurements at Interfaces with Air and 0.01 N HCl solution

Yu. M. Stryuchkova and E. V. Kasatkin

Karpov Institute of Physical Chemistry, ul. Vorontsovo pole 10, Moscow, 105054 Russia

Received November 7, 2007

Abstract — Stainless steel Kh18N10T is studied by electrochemical scanning tunneling microscopy (ESTM) and electrochemical scanning tunneling spectroscopy (ESCS) methods at the interface with air and for the fixedsample and probe potentials in 0.1 N HCl. Local spectral dependences of tunneling current on the tunneling voltage (I_t,U_t) are studied in either air or solution in the vicinity of potentials corresponding to stable properties. The local tunneling conductivity (G), the coefficient of the probability of tunneling transfer of an electron to the tip (), and the logarithmic-dependence slope ( = U_t/ln(I_t) are calculated. As for Fe–Cr alloys, it is shown that at the atomic level, the local energy properties of a steel Kh18N10T are determined by the mutual effect of neighboring atoms (the matrix effect).

The Effect of Sulfate and Nitrate Ions on the Passivation and Activation of Silver in Alkaline Solutions

N. N. Lesnykh, N. M. Tutukina, and I. K. Marshakov

Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russia

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Received December 10, 2007

Abstract — Based on the concept of a competitive adsorption of hydroxide ions with S and N activating anions, some peculiarities of the anodic behavior of silver in alkaline solutions containing sulfates or nitrates are explained. At the ascending branches of the anodic peaks, a co-adsorption of OH and S or N results in the formation of mixed adsorption complexes, which are soluble better than hydroxide ones. An increase in the part of the soluble oxidation products of silver is observed if a rotating disc electrode with a ring is used. Passivation of silver is explained by a change in the electronic structure of the adsorption complexes when certain potential values are reached, while a local activation, by the destruction of these complexes at the passive state potentials between the anodic peaks. At the depassivation, pH value of the solution in pits decreases, which results in the formation of Ag₂SO₄ or AgNO₃ salts. The presence of the salts in a deposit on the electrode is confirmed by the appearance of a C₃ cathodic peak.

PACS numbers: 82.45.Bb

Molecular Nanocrystals in Polyaniline-based Light-Emitting Diode Structures

E. I. Mal’tsev, D. A. Lypenko, O. M. Perelygina, V. F. Ivanov, O. L. Gribkova, M. A. Brusentseva, and A. V. Vannikov

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

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Received February 29, 2008

Abstract - It is found that one of the types of molecular organic nanocrystals, the so-called J-aggregates, is able to modify optoelectronic properties of electroactive polymers. It is intrinsic that the polyaniline interpolymeric complex, known as p-type semiconductor, turns into electroluminescent material in the presence of Jaggregates of 3,3-di(gamma-sulfopropyl)-5,5-dichlorotiamonomethincyanine triethylammonium salt. During the studying of new organic light-emitting diode structures, in which the polyaniline/J-aggregates polymeric composite forms both recombination and emitting layers, a polyaniline intrinsic electroluminescence spectrum is obtained. The electroluminescence band completely coincides with the polyaniline photoluminescence spectrum; it has maximum at 400 nm. The electroluminescence mechanism in the studied nanocomposites is discussed.

PACS numbers: 78.67.Bf

AFM Study of the Structuration of an Ionic Surfactant and Phenylalanine with -Carrageenan

D. V. Kolesov*^,**, T. E. Grigor’ev**, D. Yu. Gavrilko*, E. E. Makhaeva**,  I. V. Yaminskii**, and A. R. Khokhlov**

* Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

** Department of Physics, Moscow State University, Vorob’evy gory, Moscow, 119992 Russia

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Received March 6, 2008

Abstract — Local networks of -carrageenan adsorbed in the presence of an ionic surfactant and phenylalanine were examined by atomic force microscopy (AFM). Polymer chains of adsorbed carrageenan are aligned with crystallographic axes. The helical and globular conformations of carrageenan effectively bind the surfactant. Phenylalanine is not involved in the structuration of the carrageenan gel.

PACS numbers: 87.64.Dz

Conversion of the Surface Layers of Poly(Vinyl Chloride) into Aminoethyl Podand Nanofilms as a Matrix at the Surface of Borane-Selective Sorbents

A. Yu. Tsivadze, A. Ya. Fridman, N. P. Sokolova, E. M. Morozova, I. A. Gagina, A. M. Gorbunov,  A. V. Dorokhov, and A. Yu. Masanov

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,

Leninskii pr. 31, Moscow, 119991 Russia

Received June 28, 2007

PACS numbers: 68.47.Pe, 82.35.Gh

Phase Nanotomography in the Superficial Layers

V. A. Kotenev, D. N. Tyrin, and A. Yu. Tsivadze

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

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Received June 27, 2007

PACS numbers: 81.70.Tx; 78.67.-n

The Detection of the Effect of Viscosity Growth in Nanodisperse Systems during Their Shearing with Ultralow Rates

N. B. Ur’ev, Yu. S. Svistunov, A. N. Potapov, and V. A. Starikov

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

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Received March 12, 2008

Abstract — With a precision Haake RS1 rheometer, it is first found that at extremely low rates of shear ( 10³ to 10^–4 s^–1 or lower), in nanodisperse systems based on highly dispersed aerosil or aerosil–bentonite compositions, with an increase in the shear rate, a non-Newtonian flow is observed. It is accompanied with a continuous growth of the effective viscosity of the dispersions _eff, till the yield point P P_k is reached. At P P_k, the effective viscosity decreases abruptly; the structure decomposes via an aggregate mechanism. Earlier it was believed, that each viscosity level there corresponds to a combination of the full destruction of structural bonds and their partial restoring up to the equilibrium level determined by _eff. In addition, the structured dispersed system flow remains Newtonian unless the static yield point has been overcome; it corresponds to the largest viscosity of a virtually undestructed system. Using a special procedure, SEM-imaging of the structure of the bentonite-suspension, as well as the bentonite added with minor amounts of aerosil, was carried out in waterethanol medium. Photomicrographs of structure of the studied nanodisperse systems subject to shearing were obtained. The active filler (aerosil) particles distribution in the model system structure is studied. A procedure of studying the thixotropic properties of the structured nanodisperse systems in dynamic conditions is developed. The complex modeling of the structured nanodisperse system spreading over the scaled physical model, as well as special conditions of rheological tests in the Haake RS1 rotational rheometer cell, made us detecting a correlation between the spreading macroscopic factors and microscopic factors of the rheological behavior of the nanodisperse systems structure in dynamic conditions.

PACS numbers: 47.57.qk; 81.07.-b

Chemical Synthesis of Stable Nano-Sized Water-Organic Copper Dispersions

I. N. Terskaya, D. S. Sal’nikov, S. V. Makarov, O. V. Yarovaya*, and S. A. Lilin**

Ivanovo State University of Chemistry and Technology, pr. F. Engel’sa 7, Ivanovo, 153000 Russia;

* D.I. Mendeleev University of Chemical Technology of Russia, Miusskaya pl. 9, Moscow, 125047 Russia;

** Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia

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Received January 25, 2008

Abstract — The formation of aggregatively stable copper dispersions by the reduction of copper salts with thiourea dioxide or sodium hydroxymethane sulfinate in a water–organic solvent is studied. X-ray electron spectroscopy and photon correlation spectroscopy showed that the chemically formed copper exists as nano-sized particles.

Films Containing Nickel and Iron Compounds on Aluminum and Titanium

V. S. Rudnev and V. P. Morozova

Institute of Chemistry, Russian Academy of Science, Far-East Division,
pr. 100-Letiya Vladivostoka 159, Vladivostok, 690022 Russia

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Received March 19, 2007

Abstract — The composition of films formed by plasma electrochemical oxidation–deposition on aluminum and titanium in aqueous solutions containing both Ni(II) and Fe(III) polyphosphate complexes is studied. Elementary compositions of the outer part of the layers on aluminum and titanium differ insubstantially. Concentrations of nickel and iron (up to 30 wt %) in the films vary in proportion to their molar ratio in the electrolyte. Upon annealing in air, simple and multiple metal (M) oxides and phosphates crystallize in the layers, particularly, AlPO₄, NiAl₂O₄, and Fe₂O₃ on aluminum, while Ni₂P₂O₇, Ni_0.5TiOPO₄; NaTi₂(PO₄)₃, M(II)M(III)Ti(PO₄)₃, FePO₄, and Fe₂Fe(P₂O₇) on titanium.

Physicochemical Properties of Coatings Formed on Titanium by Microarc Oxidation with Energy Regulation in Breakdown Zones

P. S. Gordienko, U. V. Kharchenko, S. B. Bulanova, E. S. Panin,
V. K. Usol’tsev*, and V. A. Dostovalov*

Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia

*Far East State Technical University

Received May 3, 2007

PACS numbers: 82.45. Cc; 81.15. Pq