(256l) Ionic Current Rectification in Polyelectrolyte-Modified Conical Nanopores

Ionic current rectification in polyelectrolyte-modified conical nanopores

Hou-Hsieh Wu,* Chih-Yuan Lin, Jyh-Ping Hsu

Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 10617

ABSTRACT

   Due to their specific geometry, conical nanopores are capable of causing ion current rectification (ICR). Extending previous analyses, we consider two types of nanopore are modeled. In type 1 nanopore only the inner surface of a nanopore is functionalized by a PE layer; in type 2 nanopore both the outer and the inner surfaces of a nanopore are functionalized. A thorough numerical simulation is conducted to examine the influences of the double layer thickness and the density of the functional groups of the PE layer of a nanopore on its ICR behavior. We show that type 1 nanopore exhibits a more significant CP than type 2 nanopore does. In addition, as the bulk salt concentration varies, the rectification factors (RF) for types 1 and 2 nanopore are different significantly. If the salt concentration is low, an inversion in RF is observed in type 1 nanopore, which can be explained by the local conductivity near the nanopore tip end.

* Presenting author e-mail: r03524075@ntu.edu.tw

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