Scaling Behavior of Ionic Conductance Dependent on Surface Charge Inside a Single-Digit Nanopore
The ionic conductance in a charged nanopore exhibits a power-law behavior in low salinity—as has been verified in many experiments (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow>&...
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| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/1/191 |
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| Summary: | The ionic conductance in a charged nanopore exhibits a power-law behavior in low salinity—as has been verified in many experiments (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>∝</mo><msubsup><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>α</mi></mrow></msubsup></mrow></semantics></math></inline-formula>)—which is governed by surface charges. The surface charge inside a nanopore determines the zeta potential and ion distributions, which have a significant impact on ion transport, especially in a single-digit nanopore with potential leakage. However, precisely measuring surface charge density in a single-digit nanopore remains a challenge. Here, we propose a methodology for exploring the power-law variation of ionic conductance, with potential leakage taken into account. We conducted experiments to measure the ionic current using silicon nitride nanopores and employed a continuous theory to explore the relationship between pore-bound concentration and surface charges. Considering that the influence of potential leakage on concentration follows a power-law relationship, we established a coefficient (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>α</mi></mrow></semantics></math></inline-formula>) to examine the controlling factors of potential leakage and modified the conductance model to obtain the ion mobility inside a nanopore. |
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| ISSN: | 1420-3049 |