Analysis of particle size distribution and electro-kinetics of submicron particles in shear-thinning liquids

It needs to input the shear viscosity of carrier liquids during analyzing behaviors and properties of micron and nano-meter particles in suspensions, but it is impossible to adopt effective values for shear-thinning liquids. A method was brought forward to estimate shear viscosity based on longitudinal viscosity from acoustic attenuation and speed velocity of these liquids; then, influences of shear viscosity on both particle size distribution (PSD) and zeta potential were researched during attenuation and electroacoustic analysis of submicron ceria particles in these liquids. It was found that the aqueous carrier liquids with sodium carboxymethyl cellulose (CMC) determined by the new method should be Newtonian liquids with shear viscosity between 1.15 and 1.25 mPa·s, although they showed shear thinning and had much higher shear viscosity in limited range of shear rate during viscometer testing. Input values of shear viscosity had great influences on both PSD and zeta potential results, where d₅₀ and zeta potential had deviations as high as 5 times and 27 times, respectively. And, the deviations could be reduced to 10 to 20% when the shear viscosity of pure water was adopted. These deviations were discussed based on visco-inertial attenuation and electroacoustic theories, and these results could provide a new way to research dispersion behaviors and properties of particles in shear-thinning liquids.