Study of the aggregation state of anatase water nanofluids using rheological and DLS methods

The aggregation state of anatase water nanofluids was evaluated. Size, shape and size distribution were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM) and rheological measurements. The maximum packing fraction and the intrinsic viscosity in the limit of low and high shear rates were calculated using Krieger-Dougherty (KD) and Mooney (M) models. While the KD-model was only compatible with a monodisperse suspension of non-spherical particles, the M-model was coherent with the DLS results, and its predictions are compatible with an erosion process favoured by an increasing shear rate. Finally, an empirical viscosity model that relates the viscosity with the solid volume fraction and the shear rate is proposed.