A strategy to drive nanoflow using Laplace pressure and the end effect

Nanofluidics holds significant potential across diverse fields,including energy,environ-ment,and biotechnology.Nevertheless,the fundamental driving mechanisms on the nanoscale remain elusive,underscoring the crucial importance of exploring nanoscale driving techniques.This study introduces a Laplace pressure-driven flow method that is accurately controlled and does not interfere with interfacial dynamics.Here,we first confirmed the applicability of the Young–Laplace equation for droplet radii ranging from 1 to 10 nm.Following that,a steady-state liquid flow within the carbon nanotube was attained in molecular dynamics simulations.This flow was driven by the Laplace pressure difference across the nanochannel,which originated from two liquid droplets of unequal sizes positioned at the channel ends,respectively.Furthermore,we employ the Sampson formula to rectify the end effect,ultimately deriving a theoretical model to quantify the flow rate,which satisfactorily describes the molecular dynamics simu-lation results.This research enhances our understanding on the driving mechanisms of nanoflows,providing valuable insights for further exploration in fluid dynamics on the nanoscale.

Molecular transport under extreme confinement

Mass transport through the nanoporous medium is ubiquitous in nature and industry.Unlike the macroscale transport phenomena which have been well understood by the theory of continuum mechanics,the relevant physics and mechanics on the nanoscale transport still remain mysterious.Recent developments in fabrication of slit-like nanocapillaries with precise dimensions and atomically smooth surfaces have promoted the fundamental research on the molecular transport under extreme confinement.In this review,we summarized the contemporary progress in the study of confined molecular transport of water,ions and gases,based on both experiments and molecular dynamics simulations.The liquid exhibits a pronounced layered structure that extends over several intermolecular distances from the solid surface,which has a substantial influence on static properties and transport behaviors under confinement.Latest studies have also shown that those molecular details could provide some new understanding on the century-old classical theory in this field.