Currently, due to the development of nanotechnology and metamaterials, it has become important to obtain regular nanoporous structures with different parameters, such as porous anodic alumina films that are used for synthesis of various nanocomposites.
In this work we consider the motion of the interfaces between electrolyte and alumina layers, and between alumina and aluminum layers. We also took into account the dynamics of moving boundaries and the change of small perturbations of these boundaries. Each area under Laplace’s equation is solved for the potential of the electric field. The growth of porous alumina is described with the theory of small perturbations. Small perturbations of the interface are considered, which lead to small changes in potential and current in the boundaries.
As a result of the developed model we obtained the minimum distance between centers of aluminum oxide pores in the beginning of anodizing process and the wavelength of porous structure irregularities.
The present work is devoted to the theoretical study of the colloid nanoparticle interaction. A simple analytical model for the multi-particle interaction between the amphoteric oxide nanoparticles with low surface potential has been developed. The model utilizes the framework of the DLVO (Derjaguin, Landau, Verwey, Overbeak) theory and accounts for the surface charge regulation during the multi-particle interaction. The results of this study demonstrate a good qualitative agreement with the experimental data and reveal the presence of the orientation effects during nanoparticle aggregation, which may cause the formation of aggregates with different morphologies.
The aim of this work is the theoretical investigation of instability development of the nanoparticle surface shape during diffuse growth. The unperturbed surface is considered as an ideal sphere. The mass diffusion flux promotes increase of the sphere volume and development of free surface perturbations. The relaxation of these perturbations due to action of capillary forces is also considered along with development of small perturbations of a free surface at the expense of perturbation of a mass diffusion flux. We use the effective coefficient of viscosity μ and surface tension coefficient σ of nanoparticle to describe a surface shape relaxation. As a result there were revealed various modes at which the surface of nanoparticle loses the stability and investigated dynamics of instability development of surface.
Artificially on the surface of aluminum there may be build a thick layer of Al2O3, which has a porous structure. In this paper we present a model of growth of porous alumina in the initial stage of anodizing, identifying dependencies anodizing parameters on the rate of growth of the film and the distance between the pores and as a result of the created model equations were found for changes in the disturbance of alumina for the initial stage of anodizing aluminum oxide porous border aluminum-alumina and alumina-electrolyte, with the influence of surface diffusion of aluminum oxide.
The paper is devoted to the problem of theoretical description and modeling of the nanoparticles size distribution functions evolution. Colloidal solutions of spherical zinc oxide nanoparticles with typical dimensions of 40 – 100 nm are considered. The modified DLVO theory is used to find an analytical solution for the interaction force between nanoparticles. The resulting expression is implemented into a numerical simulation program based on Langevin dynamics method for modeling the process of nanoparticle coagulation. The character of the dependences obtained in the limits of applicability of the model corresponds well to the experimentally determined curves for similar systems.