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.