E. A. Nikitina

Quantum mechanics simulation and experimental study of adhesive interaction and aggregation of carbon-silicate nanoparticles—reinforcing fillers of polymer composites

Nanoparticles are widely used as polymer composite-reinforcing additives—fillers. Understanding the interaction mechanisms and regularities responsible for nanoparticle aggregation is of great significance for elucidating the nature of reinforcing of polymer composites. The paper reports on quantum mechanics calculations and full-scale experimental study of adhesive interaction of carbon and silicate adsorption complexes (nanomodels of active filler particles of polymer composites). The quantum mechanics approach allowed describing the adhesive properties of particle aggregates reasoning from nanoscopic structure of their surface. The quantum mechanics data were checked for adequacy on schungite—a natural mineral containing carbon and silicate. Schungite microparticles were milled to nanosizes by colloidal grinding in various disperse liquid media (alcohol, acetone, water) and the structure and properties of aggregated schungite micro- and nanoparticles were studied; fractal analysis of their surface was performed. It is found that smaller aggregates of silicate and carbon particles with higher surface fractal dimension are formed in colloidal grinding with small molecular sizes of disperse media (in our case, ethanol or methanol) and this agrees with the data predicted by quantum mechanics calculations.

Local activation of crystals by γ-rays and self-organization processes

It was shown that irradiation of the crystals with high-energy (up to 55 MeV) γ-rays leads to the prolonged self-organization of atomic displacements. A tiny portion (at about 10−9 of the sample volume) of the initially excited atoms organize the entire crystal volume with respect to the time and the space.

Aftereffects of an electric shock in BiFeO3 multiferroic

Delayed (up to several months) transformations in the atomic structure induced by the external action (electric shock) are observed for the first time in a class of nonmetals in BiFeO3 multiferroic.

Self-oscillations of the atomic structure of Nd2Fe14B nanoclusters

The phenomenon of self-oscillations of the magnetic material atomic structure, occurring at intervals of about 30 days having duration of about 150 days, was observed at the first time. The oscillations are initiated by single field pulse with duration of 1 ?s. The essence of the fluctuations was found due to the redistribution of the iron atoms over the six crystallographic non-equivalent positions. To assess the role of vacancies and boron atoms in the oscillations the vibration spectrum of substance has been calculated.