Collective modes and quantum effects in two-dimensional nanofluidic channels.

Area of Science:

• Physics
• Materials Science
• Physical Chemistry

Background:

• Nanoscale fluid transport is often studied using atomic-scale dynamics in molecular simulations.
• Fourier-space analysis, focusing on collective charge fluctuations, has successfully predicted phenomena like quantum friction and near-field heat transfer.
• Understanding these fluctuations is key to advancing nanofluidics.

Purpose of the Study:

• To investigate charge fluctuation modes within a two-dimensional nanofluidic channel.
• To generalize the concept of surface response functions for confined systems.
• To explore the impact of confinement on fluid and wall dynamics.

Main Methods:

• Utilized a Fourier-space approach to analyze charge fluctuations.
• Introduced and applied confined response functions.
• Modeled a two-dimensional planar nanofluidic channel with varying wall spacing.

Main Results:

• Confined channel walls exhibit coupled plasmon modes when confinement approaches plasmon wavelengths.
• Water fluctuations remain bulk-like until wall spacing is reduced to 7 Å.
• Predicted the dependence of quantum friction and thermal boundary conductance on channel width.

Conclusions:

• Developed a general framework for Coulomb interactions in nanoscale confined systems.
• Demonstrated that wall charge fluctuations couple significantly at smaller confinement scales.
• Highlighted the distinct confinement effects on wall versus fluid dynamics.