Interfacial transport with mobile surface charges and consequences for ionic transport in carbon nanotubes

Abstract

In this paper, we explore the effect of a finite surface charge mobility on the interfacial transport: conductance, streaming currents, electro- and diffusio-osmotic flows. We first show that the surface charge mobility modifies the hydrodynamic boundary condition for the fluid, which introduces a supplementary term depending on the applied electric field. In particular, the resulting slip length is found to decrease inversely with the surface charge. We then derive expressions for the various transport mobilities, high-lighting that the surface charge mobility merely moderates the amplification effect of interfacial slippage, to the noticeable exception of diffusio-osmosis and surface conductance. Our calculations, obtained within Poisson-Boltzmann framework, highlight the importance of non-linear electrostatic contributions to predict the small concentration/large charge limiting regimes for the transport mobilities. We discuss these predictions in the context of recent electrokinetic experiments with carbon nanotubes.

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Cited by in corpus (13)

• Fluids at the Nanoscale: from continuum to sub-continuum transport
• Osmosis, from molecular insights to large-scale applications
• Liquid-solid slip on charged walls: dramatic impact of charge distribution
• Osmotic transport at the aqueous graphene and hBN interfaces: scaling laws from a unified, first principles description
• Chemi-sorbed versus physi-sorbed surface charge and its impact on electrokinetic transport: carbon versus boron-nitride surface
• Transport of ions in hydrophobic nanotubes
• Complex coupling between surface charge and thermo-osmotic phenomena
• Slippery and mobile hydrophobic electrokinetics: from single walls to nanochannels
• Electrophoresis of ions and electrolyte conductivity: from bulk to nanochannels
• Coulombic Surface-Ion Interactions Induce Nonlinear and Chemistry-Specific Charging Kinetics
• Conductivity of concentrated salt solutions
• Enhanced zeta potentials caused by surface ion mobilities
• Enhanced transport of ions by tuning surface properties of the nanochannel