Water flow in carbon nanotubes (CNTs) starkly contradicts classical fluid mechanics, with permeabilities that can exceed no-slip Haagen-Poiseuille predictions by 2-5 orders of magnitude. Semiclassical molecular dynamics accounts for enhanced flow rates that are attributed to curvature-dependent lattice mismatch. However, the steeper permeability enhancement observed experimentally at about nanometer-size radii remains poorly understood, and suggests emergence of puzzling nonclassical mechanisms. Here, we address water-CNT friction from a quantum mechanical perspective, in terms of water-energy loss upon phonon excitation. We find that combined weak water-phonon coupling and selection rules hinder water-CNT scattering, providing effective protection to water super flow, whereas comparison with a semiclassical theory evidences a friction increase that can exceed the quantum mechanical prediction by more than 2 orders of magnitude. Quasi-frictionless flow up to subnanometer CNTs opens new pathways toward minimally invasive trans-membrane cellular injections, single-water fluidics, and efficient water filtration.

Exact Sum-Rule Approach to Polarizability and Asymptotic van der Waals Functionals – Derivation of Exact Single-Particle Benchmarks

P. L. Silvestrelli;A. Ambrosetti
2022

Abstract

Water flow in carbon nanotubes (CNTs) starkly contradicts classical fluid mechanics, with permeabilities that can exceed no-slip Haagen-Poiseuille predictions by 2-5 orders of magnitude. Semiclassical molecular dynamics accounts for enhanced flow rates that are attributed to curvature-dependent lattice mismatch. However, the steeper permeability enhancement observed experimentally at about nanometer-size radii remains poorly understood, and suggests emergence of puzzling nonclassical mechanisms. Here, we address water-CNT friction from a quantum mechanical perspective, in terms of water-energy loss upon phonon excitation. We find that combined weak water-phonon coupling and selection rules hinder water-CNT scattering, providing effective protection to water super flow, whereas comparison with a semiclassical theory evidences a friction increase that can exceed the quantum mechanical prediction by more than 2 orders of magnitude. Quasi-frictionless flow up to subnanometer CNTs opens new pathways toward minimally invasive trans-membrane cellular injections, single-water fluidics, and efficient water filtration.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3463442
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