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Liquid-Solid Slip on Charged Walls: The Dramatic Impact of Charge Distribution
Yanbo Xie1, Li Fu2, Thomas Niehaus3
1MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xian, 710072, China.
Physical Review Letters
|July 18, 2020
Summary
Surface charge significantly impacts nanofluidic energy conversion. Homogeneous surface charge enhances slip and energy conversion, while heterogeneous charge hinders it due to ion drag. This research offers guidelines for optimizing nanofluidic devices.
Area of Science:
- Nanotechnology
- Energy Conversion
- Physical Chemistry
Background:
- Nanofluidic systems offer potential for energy conversion.
- Liquid-solid slip at the nanoscale is crucial for performance.
- Surface charge is known to negatively affect slip.
Purpose of the Study:
- To investigate the impact of surface charge distribution on slip-charge coupling in nanofluidics.
- To develop theoretical models for slip-charge interactions.
- To provide guidelines for designing efficient nanofluidic energy conversion systems.
Main Methods:
- Combined molecular dynamics simulations and analytical theory.
- Investigated homogeneous and heterogeneous surface charge distributions.
- Developed a new theoretical model for slip-charge coupling.
Main Results:
- Homogeneously charged graphene shows a favorable slip-charge relation, enabling giant electrokinetic energy conversion.
- Heterogeneously charged surfaces exhibit reduced slip due to counterion-induced viscous drag.
- Slip on heterogeneous surfaces depends on interfacial physical chemistry and ion binding.
Conclusions:
- Surface charge distribution critically influences liquid-solid slip and electrokinetic energy conversion.
- Homogeneous surface charging is beneficial for maximizing energy conversion efficiency.
- Understanding ion-surface interactions is key for designing advanced nanofluidic energy harvesting devices.
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