Measurement and Modeling of Volumetric Properties of Nanofluid Containing of γ- Fe2O3 Nanoparticles Dispersed in Polyethylene glycol at Different Molar Masses

Nanoparticles of γ-Fe2O3 with size of 20nm have been dispersed in base fluids of polyethylene glycol with molar mass of 400 g.mol-1 (PEG400), PEG400+PEG2000 and PEG400+PEG6000 by using ultrasonic bath for four hours.Therefore, nanofluids of γ-Fe2O3+PEG400, γ-Fe2O3+PEG400+PEG2000 and γ-Fe2O3 + PEG400 + PEG6000 were prepared. Stability of this nanofluids has been studied by UV-Vis spectroscopy and zeta potential method. Nanoparticle sizes are specified in the base fluids using dynamic light scattering. Densities of nanofluids have been measured at temperatures of T = 298.15,308.15,318.15 K in order to study the interactions ocurred between nanoparticles and PEG. Excess molar volume values are calculated from density data. The excess molar volumes of γ-Fe2O3 + PEG400 have successfully been correlated with Ott et al. equation. These values for γ-Fe2O3 + PEG400+PEG2000 and γ-Fe2O3 + PEG400 + PEG6000 nanofluids were fitted with Sing et al. equation. Results obtained from excess molar volume have been interperated in the view point of intermolecular interactions occred between nanoparticles and PEG