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Seven Models for Outer Surface-Only Functionalized Nanofluidic Systems
Lei Xu1, Qun Ma1, Linfeng Chen1,2
1State Key Laboratory of Geomicrobiology and Environmental Changes, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
ACS Nano
|May 29, 2026
Summary
Ionic current rectification (ICR) in nanofluidics is significantly influenced by outer surface functional elements (FEOS). Synergistic effects of charge and steric hindrance on the outer surface control ICR, enabling new device designs.
Area of Science:
- Nanofluidics
- Surface Chemistry
- Electrokinetics
Background:
- Ionic current rectification (ICR) is vital for nanofluidic applications.
- Previous research focused on inner channel walls, neglecting outer surface contributions.
- Outer surface functional elements (FEOS) effects on ICR remain underexplored.
Purpose of the Study:
- To investigate the impact of outer surface functional elements (FEOS) on ICR.
- To elucidate the synergistic effects of FEOS on ionic transport.
- To demonstrate FEOS-controlled ICR for nanofluidic device design.
Main Methods:
- Modeling of porous polyethylene terephthalate nanochannels with outer surface functionalization.
- Systematic analysis of steric hindrance, surface charge, and space charge effects.
- Experimental validation using polyethylenimine as FEOS.
Main Results:
- Outer surface functional elements (FEOS) significantly impact ICR.
- Synergistic effects of surface charge, space charge, and steric hindrance are key to ICR.
- Achieved an ICR of ~1000 with FEOS functionalization at 0.1 M KCl.
Conclusions:
- FEOS play a crucial role in nanochannel electrokinetics.
- Outer surface engineering offers a new strategy for controlling ICR.
- Findings support the development of FEOS-engineered nanofluidic devices for biosensing and energy applications.
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