(262aw) Ionic Current Rectification in a Polyelectrolyte-Modified Conical Nanopore

Due to their specific geometry, conical nanopores are capable of yielding several interesting electrokinetic phenomena, such as ion concentration polarization (ICP) and ion current rectification (ICR). Extending previous analyses, we consider two types of nanopore: only the inner surface of a nanopore is functionalized by a polyelectrolyte (PE) layer in type I nanopore, and both its outer and inner surfaces are functionalized in type II nanopore. Numerical simulation is conducted to examine the influences of the double layer thickness and the thickness of the PE layer of a nanopore on its ICR behavior. We show that the ICP in type I nanopore is more significant than that in type II nanopore. In addition, as the bulk salt concentration varies, the rectification factors R_ffor type I and II nanopore are different significantly. In particular, if the salt concentration is low, an inversion in R_f is observed in type I nanopore.