Electrokinetics of non-Newtonian fluids: A review

•Electrokinetics of non-Newtonian fluids is reviewed comprehensively.•The effort is focused on the non-Newtonian effects associated with electric double layers.•Shear-thinning (thickening) enhances (weakens) electrokinetic phenomena.•Theoretical issues related to non-Newtonian electrokinetics are outlined.•Directions for the future investigations are highlighted and discussed.

This work presents a comprehensive review of electrokinetics pertaining to non-Newtonian fluids. The topic covers a broad range of non-Newtonian effects in electrokinetics, including electroosmosis of non-Newtonian fluids, electrophoresis of particles in non-Newtonian fluids, streaming potential effect of non-Newtonian fluids and other related non-Newtonian effects in electrokinetics. Generally, the coupling between non-Newtonian hydrodynamics and electrostatics not only complicates the electrokinetics but also causes the fluid/particle velocity to be nonlinearly dependent on the strength of external electric field and/or the zeta potential. Shear-thinning nature of liquids tends to enhance electrokinetic phenomena, while shear-thickening nature of liquids leads to the reduction of electrokinetic effects. In addition, directions for the future studies are suggested and several theoretical issues in non-Newtonian electrokinetics are highlighted.

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