title: Rectification of Ion Current in Nanopores Depends on the Type of Monovalent Cations: Experiments and Modeling.
abstract: Rectifying nanopores feature ion currents that are higher for voltages of one polarity compared to the currents recorded for corresponding voltages of the opposite polarity. Rectification of nanopores has been found to depend on the pore opening diameter and distribution of surface charges on the pore walls as well as pore geometry. Very little is known, however, on the dependence of ionic rectification on the type of transported ions of the same charge. We performed experiments with single conically shaped nanopores in a polymer film and recorded current-voltage curves in three electrolytes: LiCl, NaCl, and KCl. Rectification degrees of the pores, quantified as the ratio of currents recorded for voltages of opposite polarities, were the highest for KCl and the lowest for LiCl. The experimental observations could not be explained by a continuum modeling based on the Poisson-Nernst-Planck equations. All-atom molecular dynamics simulations revealed differential binding between Li+, Na+, and K+ions and carboxyl groups on the pore walls, resulting in changes to both the effective surface charge of the nanopore and cation mobility within the pore.
authors: Department of Physics and Astronomy, University of California, Irvine , Irvine, California 92697, United States.
authors: Trevor
authors: T
authors: Gamble
authors: Department of Physics, Beckman Institute, University of Illinois , Urbana, Illinois 61820, United States.
authors: Karl
authors: K
authors: Decker
authors: Department of Physics and Astronomy, University of California, Irvine , Irvine, California 92697, United States.
authors: Timothy S
authors: TS
authors: Plett
authors: Department of Physics and Astronomy, University of California, Irvine , Irvine, California 92697, United States.
authors: Matthew
authors: M
authors: Pevarnik
authors: Numerical Analysis and Scientific Computing, TU Darmstadt, Germany.
authors: Jan-Frederik
authors: JF
authors: Pietschmann
authors: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors: Ivan
authors: I
authors: Vlassiouk
authors: Department of Physics, Beckman Institute, University of Illinois , Urbana, Illinois 61820, United States.
authors: Aleksei
authors: A
authors: Aksimentiev
authors: Department of Physics and Astronomy, University of California, Irvine , Irvine, California 92697, United States ; Department of Chemistry and Department of Biomedical Engineering, University of California , Irvine, California 92697, United States ; Department of Chemistry and Department of Biomedical Engineering, University of California , Irvine, California 92697, United States.
authors: Zuzanna S
authors: ZS
authors: Siwy