I. V. Kolesnik

Electric-Field-Assisted Self-Assembly of Colloidal Particles

A method for formation of photonic crystals has been proposed. The method is based on convective deposition of colloidal particles onto vertical substrates in the presence of a direct-current electric field directed perpendicular to the surface of the formed film and an alternating-current electric field applied parallel to the substrate plane. The structure and optical properties of the prepared colloidal crystals have been investigated using scanning electron microscopy, high resolution small-angle X-ray diffraction, and optical spectroscopy.

Production of nanocrystalline titanium dioxide photoactive coatings for decomposition of organic water pollutants in a flow reactor

An efficient and technologically simple technique has been proposed for the immobilization of nanocrystalline titanium dioxide on a quartz glass. It consists in deposition of the powder from its aqueous suspension with the addition of acetylacetone. The technique makes it possible to keep the phase composition and size of the initial titanium dioxide nanoparticles, the coating uniformity, and its stability under hydromechanical treatment. The photocatalytic efficiency of the coating in the reaction of the decomposition of a methyl orange dye in an aqueous solution in a flow reactor is shown.

The thermal stability of porous anodic titania films

Porous titania films consisting of ordered aligned nanotubes have been synthesized by the method of two-stage anodic oxidation of metallic titanium at 60 V in 0.25% NH4F. The porous structure of the films has been studied by scanning electron microscopy (SEM); the thermal stability of anodic films has been investigated by SEM, XDR, thermal analysis, and IR spectroscopy. According to XRD it was established that the anodic titania film is amorphous and the amorphous titania starts to crystallize into the anatase phase under the temperature range of 300–310 °C. In addition, the coherence scattering region has been calculated from XRD data. The assumption that the porous structure does not destroy while the size of crystallites is less than the thickness of the pore wall has been confirmed by SEM data.

Mesoporous Aluminosilicates as a Host and Reactor for Preparation of Ordered Metal Nanowires

The creation of functional nanomaterials with the controlled properties is emerging as a new area of great technological and scientific interest, in particular, it is a key technology for developing novel high-density data storage devices. Today, no other technology can compete with magnetic carriers in information storage density and access rate. However, usually very small (10–1000 nm3) magnetic nanoparticles shows para- or superparamagnetic properties, with very low blocking temperatures and no coercitivity at normal conditions. One possible solution of this problem is preparation of highly anisotropic nanostructures. From the other hand, the use of purely nanocrystalline systems is limited because of their low stability and tendency to form aggregates. These problems could be solved by encapsulation of nanoparticles to a chemically inert matrix. One of the promising matrices for preparation of highly anisotropic magnetic nanoparticles is mesoporous silica or mesoporous aluminosilicates. Mesoporous silica is an amorphous SiO2 with a highly ordered uniform pore structure (the pore diameter can be controllably varied from 2 to 50 nm). This pore system is a perfect reactor for synthesis of nanocomposites due to the limitation of reaction zone by the pore walls. One could expect that size and shape of nanoparticles incorporated into mesoporous silica to be consistent with the dimensions of the porous framework.

IV International Seminar on Nonlinear Processes and Questions of Self-organization in Modern Materials Science

The major goal of the IV International Seminar on Nonlinear Processes and Questions of Self-organization in Modern Materials Science, held in Astrakhan, October 3‐5, 2002, was to highlight the general principles common in the diverse approaches to materials synthesis and characterization and to outline the critical issues in different areas of modern materials science. In most instances, materials research is concentrated on systems which evolve under highly nonequilibrium conditions and are open to energy and mass exchange with the environment. For this reason, the study of selforganization processes in physicochemical systems is of immense importance.