Viscoelastic properties of monodisperse spherical silica suspension

Abstract

The viscoelastic properties of the suspension of monodisperse spherical silica produced by hydrolysis of tetraethoxysilane in alcohol solvent with ammonia as a catalyst in polyethylene glycol (PEG) were studied. The results show that the SiO₂/PEG suspension possesses the reversible shear thinning and shear thickening behaviors. In the shear thinning region, the loss modulus (G″) almost remains unchanged, whereas the storage modulus (G′) decreases. In the shear thickening region, G″ and G′ increase for the formation of the “clusters”. The larger G″ over G′ in all the stress studied shows that the system mainly possesses the viscous property, and that the energy dissipated(E_d) is larger than that stored. E_d of this suspension is proportional to the maximum strain (γ_max) rising with the exponent of 1.92 under low shear stress; however, in the shear thickening region, E_d is proportional to γ_max rising with the exponent of 5.00.

Keywords

viscoelasticity / monodisperse silica / suspension / shear thickening