Complex Experimental Investigation of the Effect of Fullerene C60 on the Thermophysical Properties of O-Xylene

The paper summarizes the results of a comprehensive experimental study of the effect of fullerene C60 nanoparticles on the thermophysical properties of o-xylene [1]–[3]. It is shown that all investigated thermophysical properties (density, viscosity, saturated vapor pressure) in the range of fullerene concentrations of 0-0.2 wt.% behave nonmonotonically with an extremum near (0.05±0.01) wt.%. This specificity is associated with structural changes in the liquid phase that are caused by addition of fullerene. The need to take into account this effect when predicting the thermophysical properties of nanofluids in a wide range of state parameters is emphasized and the appropriate approach is proposed. It was shown that the influence of a number of factors affecting the thermophysical properties of nanofluids can be reduced to a single-factor analysis, which is the density (volume) fluctuations. In addition, it is proposed to evaluate the thermodynamic similarity of liquid systems by a similar behavior of the temperature dependences of their density (volume) fluctuations, specific heat of evaporation or isothermal compressibility.