Khanchych K. Specificities in optical and thermophysical properties of the system of (fullerene C60)-(o-xylene)

The thesis is devoted to a complex investigation of optical and thermophysical properties of solutions of fullerene C60 in o-xylene in order to establish the physical nature of their anomalous concentration behavior, to explain the phenomenon of structuring the base fluid with a small amount of fullerene additives and to solve the problem of finding a universal approach to accounting the contribution of nanoparticles on the structure and properties of base fluids.The results of a complex experimental study of the effect of fullerene C60 nanoparticles on the optical (optical density) and thermophysical (density, viscosity, saturated vapor pressure, surface tension) properties of o-xylene in a wide range of state parameters are analyzed. It is shown that the structural changes of the base fluid are reflected on all mentioned properties of the studied system as an anomalous concentration behavior.Based on the ideas of the fluctuation theory of liquids and obtained results, it is proposed to use the character of temperature and concentration behavior of the mean square density (volume) fluctuations as a determining factor in the anomalous behavior of the thermophysical properties of nanofluids.Two models for calculating the viscosity of fullerene-containing nanofluidsare proposed. The first one is based on the thermodynamic similarity of nanofluids and the base fluid, the second one – on the concept of free volume. An analytical model for calculating the surface tension of fullerene-containing nanofluids using data on the saturated vapor pressure is developed.