Shear Rheology of Silica Nanoparticle Dispersions

Abstract

The effects of particle concentration, particle size and temperature on the shear rheology of suspensions of silica nanoparticles are studied. Sterically or electrostatically stabilized silica nanoparticle dispersions with sizes ranging from 5-75 nm and particle volume fractions ranging from 0.22-25 % exhibited a constant viscosity within the shear rate range of 1-200 s-1. There is a non-linear relationship between the concentration and the viscosity of these dispersions that depends on the radii and surface energy of these nanoparticles. We propose an effective maximum packing fraction model based on the concept of an effective particle radius, which takes into account the thickness of the electrical double layer and the surface coating material. The viscosities of all the dispersions collapse onto a universal curve as a function of the volume fraction normalized by the effective maximum packing fraction.

Keywords

• silica nanoparticles
• particle size
• surface coating
• effective maximum packing fraction
• shear rheology