Electrophoresis of soft particles in a non-Newtonian power-law fluidic microenvironment.

This article focuses on the electrophoresis of pH-regulated core-shell structured soft particles suspended in a non-Newtonian fluid modeled by a power-law rheology. It addresses the complex coupling between electrostatics and non-Newtonian fluid behavior, extending beyond classical Debye–Hückel theory to numerically and analytically determine electrophoretic velocities under various electrostatic and hydrodynamic limits. The study reveals that particle velocity is significantly enhanced in shear-thinning fluids and decreases with increasing flow behavior index due to viscous effects, with the Brinkmann screening length of the polyelectrolyte layer (PEL) strongly influencing electrophoretic motion. Analytical expressions are derived for electrophoretic velocity in limiting cases of Brinkmann screening length and electric double layer thickness, and numerical results are validated against these expressions and experimental data. The findings highlight the importance of considering soft particle surface structures and non-Newtonian fluid properties for accurate prediction of electrophoretic behavior in biological and environmental contexts.