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Modulation of ionic current rectification in short unipolar nanopores
Hongwen Zhang1, Long Ma1, Di Liu2
1Key Laboratory of High Efficiency and Clean Mechanical Manufacture of the Ministry of Education, State Key Laboratory of Advanced Equipment and Technology for Metal Forming, School of Mechanical Engineering, Shandong University, Jinan 250061, China; Shenzhen Research Institute of Shandong University, Shenzhen 518000, China.
Journal of Colloid and Interface Science
|October 24, 2025
Summary
Controlled ionic current rectification (ICR) in nanopores is optimized by strategically designing surface charge distribution. A charged-length proportion of approximately 0.3 on pore walls maximizes ICR, crucial for nanofluidic devices.
Area of Science:
- Nanotechnology
- Physical Chemistry
- Materials Science
Background:
- Unipolar nanopores with non-uniform surface charge distributions enable ionic current rectification (ICR).
- ICR is vital for applications like nanofluidic sensors, ionic circuits, and ion amplifiers.
- Understanding how surface charge modulates ion transport is key to optimizing nanopore performance.
Purpose of the Study:
- To systematically investigate the influence of charged length on inner pore walls on ion transport and ICR.
- To determine the optimal charged-length proportion for maximizing ICR in short unipolar nanopores.
- To analyze the effect of exterior surface charges on enhancing ICR and their relationship with nanopore parameters.
Main Methods:
- Computational simulations were used to model ion transport through unipolar nanopores.
- Systematic variation of charged length, pore diameter, salt concentration, and applied voltage.
- Analysis of ion enrichment and depletion within the nanopore under varying conditions.
Main Results:
- The maximum ICR degree for 100 nm unipolar nanopores occurs at a charged-length proportion of approximately 0.3.
- This optimal proportion (∼0.3) is consistent across various simulation conditions and nanopore parameters.
- Exterior surface charges significantly enhance ICR by facilitating ion transport, with effective widths dependent on pore geometry, charge density, voltage, and salt concentration.
Conclusions:
- A charged-length proportion of ∼0.3 is a characteristic value for maximizing ICR in short unipolar nanopores.
- Exterior surface charges play a crucial role in enhancing ICR, offering a design strategy for improved performance.
- This research provides valuable insights for designing unipolar nanopores and porous membranes with tailored charge configurations for advanced nanofluidic applications.
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