Magnetorheological and Volumetric Properties of Starch and Polyethylene Glycol Solutions in the Presence of NiO Nanoparticles

The effect of NiO nanoparticles on the rheological and volumetric properties of the dilute solutions of starch-NaOH-H2O, PEG400- PEG2000 and PEG400-PEG6000 was investigated. To this end, the stable nanofluids should have bee prepared, therefor, the nanoparticles of NiO were added to these solutions and dispersed by a shaker and an ultrasonic bath for making the homogeneous nanofluids. The UVVis spectroscopy, zeta potential and dynamic light scattering were used to specify the stability and particle size distribution of colloidal solutions studied. Fluid flow and suspense structure of NiO nanoparticles in the solutions of starch-NaOH-H2O, PEG400-PEG2000 and PEG400-PEG6000 were studied by measuring the magnetorheological properties at T = 298.15 K. Pseudoplastic (or shear-thinning) behavior was observed for all the suspensions investigated. Bingham plastic, Herschel-Bulkley and Carreau-Yasuda models were applied for modeling the magnetorheological properties of nanofluids. The density values of NiO-starch-NaOH-H2O, NiO-PEG400-PEG2000 and NiO-PEG400-PEG6000 nanofluids were also measured at T = (298.15, 308.15 and 318.15) K. The excess molar volumes were calculated from the density data for highlighting the interparticle interactions occurred in the nanofluids. Singh et al. equation was used for fitting the excess molar volume values. The trend of excess molar volumes of nanofluids with concentration indicated that the significant interactions observed in NiO-starch-NaOH-H2O nanofluid are attractive interactions and in NiO-PEG400-PEG2000 and NiO-PEG400-PEG6000 colloidal solutions are van der Waals-type interactions.