Thermophysical, Optical, and Mass Transport Properties of C60 Fullerene Solutions in Toluene and Tetralin

ABSTRACT: We have measured isothermal and non-isothermal mass transport properties of fullerene C60 in two different organic solvents, tetralin and toluene, and compared these measurements with the respective properties of the binary mixture of the pure solvents. In addition, a set of thermophysical and optical properties of the mixtures needed for extraction of the transport properties was measured and parameterized. Five different instruments used in this work for assessing the transport properties were extensively tested and benchmarked previously and have shown reliable and accurate results. The use of the instruments allowed us to provide the diffusion, thermodiffusion, and Soret coefficients at 298.15 K and normal pressure with an accuracy better than 5%. The hydrodynamic radii calculated from the diffusion coefficients agree with literature values for the fullerene radius, which proves the absence of fullerene aggregation in the studied mixtures. While the values of diffusion coefficients are within the range typical for molecular mixtures, the Soret coefficients are an order of magnitude higher and fall into the gap between ordinary molecular mixtures (ST < 10-2 K-1) and colloids/nanofluids (ST > 10-1 K-1).