Complex viscous behaviour of a hydrophilic fumed silica suspension: Temperature and particle concentration influence

Abstract

• Shear-thickening dependence on temperature and solid concentration. • New criteria for shear-thickening intensity. • Variation of the shear-thickening microstructure with shear stress. • Intrinsic viscosity and activation entropy for the viscous flow increasing with shear stress. Shear-thickening (ST) is a non-Newtonian viscous behaviour characterized by the increase of the steady viscosity by shearing. It is well known that applied stress better than shear rate is the source of fluid inner microstructure changes which lead to non-Newtonian behaviours. Therefore, the influence of temperature and solid concentration on the stress-induced complex steady viscous behaviour shown by a hydrophilic fumed silica suspension (A200PPG400) has been studied. Previous works have demonstrated that hydroclusters model is the appropriate approach justifying the ST behaviour of A200PPG400 suspensions. In this work, more detailed description of this ST mechanism has been proposed based upon the analysis of intrinsic viscosity and activation energy for the viscous flow experimental data.