skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Gating of Hydrophobic Nanopores with Large Anions

Journal Article · · ACS Nano

In this report, understanding ion transport in nanoporous materials is critical to a wide variety of energy and environmental technologies, ranging from ion-selective membranes, drug delivery, and biosensing, to ion batteries and supercapacitors. While nanoscale transport is often described by continuum models that rely on a point charge description for ions and a homogeneous dielectric medium for the solvent, here, we show that transport of aqueous solutions at a hydrophobic interface can be highly dependent on the size and hydration strength of the solvated ions. Specifically, measurements of ion current through single silicon nitride nanopores that contain a hydrophobic-hydrophilic junction show that transport properties are dependent not only on applied voltage but also the type of anion. We find that in Cl- -contained solutions the nanopores only conducted ionic current above a negative voltage threshold. On the other hand, introduction of large polarizable anions, such as Br- and I-, facilitated the pore wetting, making the pore conductive at all examined voltages. Molecular dynamics simulations revealed that the large anions, Br- and I-, have a weaker solvation shell compared to that of Cl-, and consequently were prone to migrate from the aqueous solution to the hydrophobic surface, leading to the anion accumulation responsible for pore wetting. The results are essential for designing nanoporous systems that are selective to ions of the same charge, for realization of ion-induced wetting in hydrophobic pores, as well as for fundamental understanding on the role of ion hydration shell on the properties of solid/liquid interfaces.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC52-07NA27344
OSTI ID:
1844485
Report Number(s):
LLNL-JRNL-780232; 973962
Journal Information:
ACS Nano, Vol. 14, Issue 4; ISSN 1936-0851
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (71)

Generalized Gradient Approximation Made Simple journal October 1996
Surface Propensities of Atmospherically Relevant Ions in Salt Solutions Revealed by Phase-Sensitive Sum Frequency Vibrational Spectroscopy journal July 2011
Effect of Field Direction on Electrowetting in a Nanopore journal March 2007
Rectification of Ionic Current in a Nanofluidic Diode journal March 2007
Structure in aqueous solutions of nonpolar solutes from the standpoint of scaled-particle theory journal January 1973
In Situ Nanopore Fabrication and Single-Molecule Sensing with Microscale Liquid Contacts journal April 2017
On the Nature of ions at the Liquid Water Surface journal May 2006
Intrusion and extrusion of water in hydrophobic mesopores journal March 2004
Electron Spectroscopy of Aqueous Solution Interfaces Reveals Surface Enhancement of Halides journal January 2005
Modulation of hydrophobic interactions by proximally immobilized ions journal January 2015
Specific ion effects in aqueous eletrolyte solutions confined within graphene sheets at the nanometric scale journal January 2012
A hydrophobic gate in an ion channel: the closed state of the nicotinic acetylcholine receptor journal June 2006
Architecture of Qbox: A scalable first-principles molecular dynamics code journal January 2008
Hydration Behavior under Confinement by Nanoscale Surfaces with Patterned Hydrophobicity and Hydrophilicity journal December 2006
Hydration properties of mechanosensitive channel pores define the energetics of gating journal October 2010
Continuous assembly of supramolecular polyamine–phosphate networks on surfaces: preparation and permeability properties of nanofilms journal January 2019
Comparison of bipolar and unipolar ionic diodes journal June 2010
Numerical integration of the cartesian equations of motion of a system with constraints: molecular dynamics of n-alkanes journal March 1977
Nanopore Fabrication by Controlled Dielectric Breakdown journal March 2014
Computational Study of Ion Binding to the Liquid Interface of Water journal October 2002
Fast Parallel Algorithms for Short-Range Molecular Dynamics journal March 1995
Fluctuations of Water near Extended Hydrophobic and Hydrophilic Surfaces journal February 2010
Voltage-Gated Hydrophobic Nanopores journal August 2011
Vibrational Spectroscopy of Aqueous Sodium Halide Solutions and Air−Liquid Interfaces:  Observation of Increased Interfacial Depth journal February 2004
Ion-Specific Anomalous Electrokinetic Effects in Hydrophobic Nanochannels journal April 2007
Study of Penetration of Water into Hydrophobized Porous Silicas journal March 1997
Transport phenomena in nanofluidics journal July 2008
Salt Solutions in Carbon Nanotubes: The Role of Cation−π Interactions journal March 2016
Towards an assessment of the accuracy of density functional theory for first principles simulations of water. II journal September 2004
Molecular Structure of Salt Solutions:  A New View of the Interface with Implications for Heterogeneous Atmospheric Chemistry journal November 2001
Perfluoroalkanes:  Conformational Analysis and Liquid-State Properties from ab Initio and Monte Carlo Calculations journal April 2001
Nanofluidic Ionic Diodes. Comparison of Analytical and Numerical Solutions journal July 2008
Intrusion and extrusion of water in hydrophobic nanopores journal November 2017
A unified formulation of the constant temperature molecular dynamics methods journal July 1984
Anisotropic structure and dynamics of water under static electric fields journal February 2019
The molecular structure of the interface between water and a hydrophobic substrate is liquid-vapor like journal November 2014
Concentration-Polarization-Induced Precipitation and Ionic Current Oscillations with Tunable Frequency journal January 2018
Water Dynamics and Dewetting Transitions in the Small Mechanosensitive Channel MscS journal May 2004
Ions at the Air/Water Interface journal June 2002
Development and Testing of the OPLS All-Atom Force Field on Conformational Energetics and Properties of Organic Liquids journal January 1996
Electric-field-induced wetting and dewetting in single hydrophobic nanopores journal October 2011
Hydrophobic Gating in Ion Channels journal January 2015
Water Confinement in Hydrophobic Nanopores. Pressure-Induced Wetting and Drying journal August 2010
Charge Inversion and Calcium Gating in Mixtures of Ions in Nanopores journal January 2020
Propensity of soft ions for the air/water interface journal August 2004
Voltage Gating of a Biomimetic Nanopore: Electrowetting of a Hydrophobic Barrier journal February 2017
Molecular dynamics with coupling to an external bath journal October 1984
Liquid-vapor oscillations of water in hydrophobic nanopores journal May 2003
Mechanism of ion adsorption to aqueous interfaces: Graphene/water vs. air/water journal August 2017
Interfaces and the driving force of hydrophobic assembly journal September 2005
Solvent fluctuations in hydrophobic cavity–ligand binding kinetics journal January 2013
Probing the Interfacial Structure of Aqueous Electrolytes with Femtosecond Second Harmonic Generation Spectroscopy journal July 2006
Introducing Chemical Transport Selectivity into Gold Nanotubule Membranes journal July 1998
Presence of electrolyte promotes wetting and hydrophobic gating in nanopores with residual surface charges journal January 2015
Towards an assessment of the accuracy of density functional theory for first principles simulations of water journal January 2004
Surface topography dependence of biomolecular hydrophobic hydration journal April 1998
Canonical dynamics: Equilibrium phase-space distributions journal March 1985
Deconstructing Classical Water Models at Interfaces and in Bulk journal August 2011
Giant Osmotic Pressure in the Forced Wetting of Hydrophobic Nanopores journal July 2015
Access resistance of a small circular pore journal October 1975
Electric-field-controlled water and ion permeation of a hydrophobic nanopore journal June 2005
Voltage-dependent ordering of water molecules at an electrode–electrolyte interface journal March 1994
Optimization algorithm for the generation of ONCV pseudopotentials journal November 2015
Ions at Hydrophobic Aqueous Interfaces: Molecular Dynamics with Effective Polarization journal July 2012
The Hydrophobic Effect Contributes to the Closed State of a Simplified Ion Channel through a Conserved Hydrophobic Patch at the Pore-Helix Crossing journal November 2015
Molecular Mechanism of Ion Binding to the Liquid/Vapor Interface of Water journal January 2002
Biosensing with Nanofluidic Diodes journal June 2009
Sitting at the Edge: How Biomolecules use Hydrophobicity to Tune Their Interactions and Function journal February 2012
Ion spatial distributions at the liquid–vapor interface of aqueous potassium fluoride solutions journal January 2008
Engineered voltage-responsive nanopores journal January 2010
Structure and dynamics of aqueous solutions from PBE-based first-principles molecular dynamics simulations journal October 2016

Similar Records

Rectified and Salt Concentration Dependent Wetting of Hydrophobic Nanopores
Journal Article · Tue Jun 21 00:00:00 EDT 2022 · Journal of the American Chemical Society · OSTI ID:1844485

Voltage-Gated Hydrophobic Nanopores
Journal Article · Sat Jan 01 00:00:00 EST 2011 · ACS Nano · OSTI ID:1844485

Molecular Dynamics Simulations of Anion Exclusion in Clay Interlayer Nanopores
Journal Article · Mon Aug 01 00:00:00 EDT 2016 · Clays and Clay Minerals · OSTI ID:1844485