A simulation study on ionic current in cylindrical hydrophobic nanopores

The ionic current and electroosmotic flow (EOF) in hydrophobic nanopores are studied numerically. The Poisson, Navier-Stokes, and Nernst-Planck equations were solved simultaneously by finite element method. For the characterization of hydrophobic nanopores, the Navier-slip boundary condition was replaced the no-slip boundary condition on the surface of the nanopore. The effect of hydrophobicity on different ionic current mechanisms is investigated. Also, the effects of voltage difference and electrolyte concentration on ionic current in hydrophobic nanopores are studied. The results show that nanopore hydrophobicity affects the convective and electrophoretic ionic current significantly. Due to the EOF enhancement by increasing the nanopore’s slip length, the convective ionic current signifies, and the electrophoretic ionic current dwindles. In addition, by increasing the slip length of the nanopore, the total ionic current and EOF in all cases grows. The effect of hydrophobicity on the ionic current in the electrolytes with high concentration is more than weak electrolytes.