Modulation of the electrokinetic streaming potential, as a function of the zeta potential and fluid slip

Pressure-driven electrokinetic flows for obtaining large streaming potential (Vs) were investigated over a large range of surface zeta potentials (zeta), i.e., up to 150 mV, and slip lengths (b), i.e., from 1 -50 nm. A maximum in the Vs with respect to the zeta was noted, with a shift of the maximum to lower zeta with increasing b. The obtained results imply a necessary re-interpretation of the Helmholtz-Smoluchowski relation, which posits a linear variation of the Vs with the zeta and b. Both analytical modeling and numerical simulations were utilized to verify the conclusions.