Rheological Behavior of Concentrated Monodispersed Colloidal Suspensions

The effect of suspending medium on the rheological behavior of monodispersed colloidal suspensions was examined to identify the characteristic rheological behavior of concentrated colloidal suspensions. Colloidal suspensions of monodispersed silica particles form colloidal crystals and exhibit shear-thinning flows. With the change of the suspending medium from an aqueous medium to a polyethylene-glycol di-acrylate monomer, both the viscosity of the suspensions and the degree of shear-thinning decreased, and the suspensions exhibited shear-thickening behavior under high shear rates. Additionally, increasing the particle size, critical shear-rate and critical shear-stress at the onset of shear-thickening decreased. Finally, the research found that shear-thickening becomes more noticeable as the increase in the ethylene-glycol chain lengths of the monomer and the particle size.