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Dynamic Response of Ionic Current in Conical Nanopores.
Zhe Liu1,2, Long Ma1, Hongwen Zhang1
1Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education, National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China.
ACS Applied Materials & Interfaces
|June 3, 2024
Summary
Ionic current rectification in charged conical nanopores depends on ion enrichment and depletion dynamics. Nanopore response time varies significantly between "on" and "off" states, influenced by pore geometry and electrical conditions.
Area of Science:
- Nanofluidics
- Biophysics
- Materials Science
Background:
- Ionic current rectification (ICR) in charged conical nanopores is crucial for nanofluidics, biosensing, and energy conversion.
- The dynamic response of nanopores, particularly ion enrichment and depletion, dictates ICR performance.
- Voltage scanning rates influence the formation of ion enrichment and depletion zones.
Purpose of the Study:
- To investigate the dynamic response of ion current in conical nanopores under electric fields.
- To analyze the formation kinetics of ion enrichment and depletion.
- To elucidate the relationship between nanopore parameters, applied conditions, and response time.
Main Methods:
- Time-dependent simulations of ionic current flow in charged conical nanopores.
- Analysis of voltage-dependent ion enrichment and depletion dynamics.
- Parametric study involving surface charge density, pore geometry, voltage, and bulk concentration.
Main Results:
- The response time for ion enrichment ('on' state) is significantly longer than for ion depletion ('off' state).
- Nanopore response time is modulated by surface charge density, pore length, tip/base radii, applied voltage, and bulk ion concentration.
- A clear correlation exists between nanopore parameters/conditions and the dynamic response of ionic current.
Conclusions:
- The dynamic response mechanism of ionic current in conical nanopores is uncovered.
- Understanding these dynamics is key to designing advanced nanofluidic devices.
- Findings can guide the development of nanopore-based memristors, ionic switches, and rectifiers.
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