Voltage-controlled ion transport and selectivity in a conical nanopore functionalized with pH-tunable polyelectrolyte brushes
Journal
Journal of Colloid and Interface Science
Journal Volume
537
Pages
496-504
Date Issued
2019
Author(s)
Abstract
Chemically functionalized bioinspired nanopores are widely adopted to control the ionic transport for various purposes. A detailed understanding of the underlying mechanisms is not only desirable but also necessary for device design and experimental data interpretation. Here, the conductance and the ion selectivity of a conical nanopore surface modified by a polyelectrolyte (PE) layer are studied through adjusting the pH, the bulk salt concentration, and the level of the applied potential bias. Possible mechanisms are proposed and discussed in detail. We show that the conductance is sensitive to the variation in the solution pH. The ion selectivity of the nanopore is influenced significantly by both the solution pH and the level of the applied potential bias. In particular, a cation-selective nanopore might become anion-selective through raising the applied potential bias. The ion transport behavior can be tuned easily by adjusting the level of pH, salt concentration, and applied potential bias, thereby providing useful information for the design of nanopore-based sensing devices. ? 2018 Elsevier Inc.
Subjects
Ion selectivity
Nanopore conductance
pH-tunable
Polyelectrolyte modification
SDGs
Type
journal article