SUSU Scientists are Developing a Method for Obtaining Radiation-Resistant Nanocomposites

Creating new materials is one of the main areas of contemporary nanotechnologies. The most prioritized research goals include creating materials with preliminarily set properties. Scientists of South Ural State University developed a theoretical model which allows determining parameters of a nanocomposite with desired characteristics.

The project entitled “Electro physical properties of nanocomposite materials” became winner of the Scientific Perspective contest which was held within the frameworks of Project 5-100. Its scientific supervisor is Doctor of Sciences (Physics and Mathematics), Professor Alexander Yalovets. Author of the project, postgraduate student of the Institute of Natural SciencesNatalia Dyuryagina, told us about properties of the developed materials and the possibilities of their use.

“Nowadays nanocomposites are used in all spheres of science and technology, and the necessity to create new functional materials and studying their electro physical properties is constantly increasing. Nanocomposite materials are obtained by injecting nano-sized particles into the material. Depending on which materials we choose as the injection and matrix, we obtain a new functional material with unique properties. These properties depend on the size, concentration and form of nanoparticles. There are many experimental works in this sphere, but there is still no a specific theoretical model which would consider all processes taking place in this complex material,” notes Natalia Dyuryagina. “The goal of my work is to create such theoretical model. Using such model, it will be possible to predict properties of one nanocomposite or another, or select parameters necessary for creating a specific material with desired properties.”

The project is dedicated to researching two nanocomposite materials: polymethylmethacrylate with inclusion of cadmium sulfide and alumina with inclusion of strontium oxide. The first material is used while creating various optoelectronic, photovoltaic devices, and new elements for telecommunication systems (for example, semi-conductive photoelectric receivers). It is necessary to consider the possibility of using such devices under conditions of increased radiation. On the contrary, alumina and nanocomposites on its basis are sensible to absorbed dose of ionizing radiation and get used in dosimetry.

“The choice of polymethylmethacrylate is caused by its transparence to visible and short-range ultraviolet emission and its high insulating and physical-and-mechanical properties. Polymethylmethacrylate itself is radiation-unstable, however when injecting nanoparticles of cadmium sulfide, a radiation-resistant nanocomposite is obtained. This allows using it in nuclear power engineering when producing devices and equipment intended for space. Performance of such devices won’t be affected by radiation background. This is one of the primal objectives that we’ve set. The second objective is connected with the fact that alumina itself is very sensitive to radioactive emission. It is used in dosimetry along with composites on its basis. At the moment, I am trying to find out how exactly the inclusion of nanoparticles influences material’s sensitivity to radioactive emission, and try to determine the most optimal parameters of a nanocomposite.”

Semi-conducting nanoparticles such as cadmium sulfide are able to glow across a broad range of wave length. Size-dependable properties of nanoparticles are connected with quantum-dimensional effects which are the stronger the smaller is the size of nanoparticles. However, for maximal implementation of their optic properties, it is necessary to protect nanoparticles from chemical exposure of the environment and isolate them from one another. For that, nanoparticles get injected to polymeric matrices.

“Nowadays there is not such a model which would prevent radioactive properties, radioactive conductivity or the range of nanocomposites’ luminescence,” notes Natalia Dyuryagina. “Our research is based on the system of Rose-Fowler equations. We developed an efficient method for solving this system of equations, and this method can already be used for nanocomposites, i.e. consider the inclusion of nanoparticles. This research will allow for optimizing the choice of parameters of nanocomposites (materials of the matrix and inclusions, the size and concentration of inclusions) with the goal of obtaining a new material with set properties. When researching the two nanocomposites which are used for absolutely controversial objectives, we discovered patterns of formation of radioactive conductivity of the nanocomposite materials depending on the intensity and duration of ionizing radiation, and on the size and concentration of inclusions.”

At the present time, the developed theoretical model allows for determining radioactive conductivity of pure material and nanocomposite, and electric conductivity of nonexposed material. The next stage of the project implementation will be improving the model in order to obtain specters of thermal and photo luminescence of nanocomposite materials. During experiments the absorbed dose of ionizing radiation is determined based precisely on the specter’s data.

Viktoria Matveychuk
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