Ion steric interactions and electrostatic correlations on electro-osmotic flow in charged nanopores with multivalent electrolytes

In this study we have extended the mean-field based model to analyze the layered structure of the electric double layer and found that oscillations in charge density arise in multivalent counterions. Formation of the counterion condensed layer and overscreening creates a larger accumulation of coions in the electric double layer, leading to an electroosmotic flow reversal and attenuation in ion selectivity of the pore. The present model shows that the counterion size has an impact on the condensed layer and hence, overscreening. We demonstrate that the electroosmotic flow reversal of multivalent electrolytes can be suppressed by mixing with monovalent slats.