Nanofluidics, from bulk to interfaces

TL;DR

This review explores the unique properties and phenomena of fluids at nanometer scales, emphasizing the interplay between bulk and interface effects, and discusses the limits of continuum models and electro-kinetic phenomena in nanofluidics.

Contribution

It provides a comprehensive overview of nanofluidic phenomena, highlighting the importance of surface effects and the analogy with semiconductor ion transport, advancing understanding of nanoscale fluid behavior.

Findings

Surface effects dominate at nanoscales

Hydrodynamic slippage influences flow behavior

Electro-kinetic phenomena are significant in nanofluidics

Abstract

Nanofluidics has emerged recently in the footsteps of microfluidics, following the quest of scale reduction inherent to nanotechnologies. By definition, nanofluidics explores transport phenomena of fluids at the nanometer scales. Why is the nanometer scale specific ? What fluid properties are probed at nanometric scales ? In other words, why 'nanofluidics' deserves its own brand name ? In this critical review, we will explore the vast manifold of length scales emerging for the fluid behavior at the nanoscales, as well as the associated mechanisms and corresponding applications. We will in particular explore the interplay between bulk and interface phenomena. The limit of validity of the continuum approaches will be discussed, as well as the numerous surface induced effects occuring at these scales, from hydrodynamic slippage to the various electro-kinetic phenomena originating from the couplings between hydrodynamics and electrostatics. An enlightening analogy between ion transport in nanochannels and transport in doped semi-conductors will be discussed.