Improved ionic current rectification utilizing cylindrical nanochannels coated with polyelectrolyte layers of...

Area of Science:

• Nanofluidics
• Physical Chemistry
• Materials Science

Background:

• Conical nanochannels are used for ionic current rectification (ICR) but are prone to clogging.
• Clogging in conical nanochannels is caused by the channel's contraction.
• There is a need for alternative designs that offer efficient ICR with improved durability.

Purpose of the Study:

• To propose and investigate a cylindrical nanochannel coated with a polyelectrolyte layer (PEL) as an alternative for ICR.
• To analyze the performance of this new design and compare it with traditional conical nanochannels.
• To explore the fundamental mechanism of ICR in the proposed system.

Main Methods:

• Numerical simulation by solving Poisson, Nernst-Planck, and Stokes-Brinkman equations.
• Development of a simplified one-dimensional model to explain the ICR mechanism.
• Systematic investigation of parameters including nanochannel radius, PEL fixed charge concentration, and bulk ionic concentration.

Main Results:

• The proposed cylindrical nanochannel with PEL demonstrates superior rectification factors compared to conical nanochannels.
• Higher performance is achieved across a broad range of fixed charge and bulk ionic concentrations.
• The design allows for larger channel radii, reducing clogging probability and enhancing service life.

Conclusions:

• Cylindrical nanochannels with PEL offer a promising alternative for creating efficient and durable ionic current rectification.
• This design overcomes the clogging limitations of conical nanochannels.
• The proposed nanochannel has the potential for widespread adoption in nanofluidic devices as a replacement for conical diodes.