Covering the conical nanochannels with dense polyelectrolyte layers significantly improves the ionic current...

Area of Science:

• Nanotechnology
• Electrokinetics
• Physical Chemistry

Background:

• Conical nanochannels exhibit unique electrokinetic phenomena due to asymmetry.
• Polyelectrolyte layer (PEL)-covered nanochannels show distinct ionic current rectification.
• Existing models often assume uniform PEL and electrolyte properties, which is inaccurate for dense PELs.

Purpose of the Study:

• Investigate the impact of differing PEL and electrolyte properties on ionic current rectification in conical soft nanochannels.
• Analyze how variations in permittivity, diffusivity, and viscosity affect rectification behavior.

Main Methods:

• Employed a finite-element approach to solve Poisson-Nernst-Planck and Navier-Stokes equations.
• Simulated steady-state conditions considering distinct PEL and electrolyte properties.
• Validated the model against existing theoretical and experimental data.

Main Results:

• Property differences between the PEL and electrolyte significantly enhance ionic current rectification.
• Improvement in rectification is particularly notable at low and moderate salt concentrations.
• The study demonstrates the critical importance of accounting for disparate PEL-electrolyte properties.

Conclusions:

• The findings underscore the necessity of differentiating PEL and electrolyte properties in soft nanochannel modeling.
• Utilizing denser PELs offers a pathway to considerably improve the rectification performance of soft nanochannels/nanopores.