Dependence of Nonlinear Electrophoresis on Particle Size and Electrical Charge

This study focuses on the dependence of nonlinear electrophoretic migration of particles on the particle size and particle electrical charge. This is the first report of the experimental assessment of the mobilities of the nonlinear electrophoretic velocity of colloidal polystyrene microparticles under two distinct electric field dependences. A total of nine distinct types of polystyrene microparticles of varying size and varying electrical charge were divided into two groups to study separately the effects of particle size and the effects of particle charge. The mobilities of the nonlinear electrophoretic velocity of each particle type were determined in both the cubic and 3/2 regimes (μ_EP,NL⁽³⁾ and μ_EP,NL^(3/2)). The results unveiled that both mobilities had similar relationships with particle size and charge. The magnitude of both μ_EP,NL⁽³⁾ and μ_EP,NL^(3/2) increased with increasing particle size and decreased with increasing magnitude of particle charge. However, the observed trends were not perfect as discussed in the Results and Discussion section but still provide valuable information. These findings will aid in the design of future size-based and charge-based separations of particles and microorganisms.