Molecular Friction Trumps Viscosity in Angstrofluidic Transport

Area of Science:

• Nanofluidics
• Statistical Mechanics
• Molecular Dynamics

Background:

• Classical continuum theories are inadequate for ultra-confined nanofluidic systems.
• Fundamental fluid properties lose conventional meaning at the molecular scale.

Purpose of the Study:

• To address the limitations of continuum theories in nanofluidics.
• To develop a new framework for understanding fluid transport at the molecular level.
• To define a continuum-referenced resistance metric.

Main Methods:

• Molecular dynamics simulations of liquid argon transport through graphene nanopores and carbon nanotubes.
• Application of statistical mechanics principles, including the ergodic hypothesis.
• Reconstruction of velocity distributions from atomic trajectories.

Main Results:

• Defined a continuum viscosity coefficient (CVC) as a resistance metric, distinct from effective viscosity.
• Established a physically inspired mapping between atomistic simulations and continuum surrogates.
• Revealed dependencies of flow resistance on wall-fluid interactions and geometric confinement.

Conclusions:

• The developed framework provides predictive design tools for sub-nanometer fluidic devices.
• This approach offers a new perspective for translating molecular-scale behavior into engineering insights.
• Implications for nanofiltration, ion sieving, and semiconductor processing.