Comparative Molecular Dynamics Study of Interfacial Transport Characteristics of Layered Graphite and Hexagonal Boron Nitride

A molecular understanding of interfacial transport characteristics such as fluid slip and surface ionic conductivity is necessary for the design of pores exhibiting tailored functionality for applications in nanofluidics and membrane science (e.g., blue energy generation and desalination). The expression of surface interactions exhibits strong material-dependance, illustrated by the comparison of fluid slip measurements in graphitic materials (Gr)—such as carbon nanotubes and layered graphite channels—and hexagonal boron nitride (hBN); in this case, despite the nearly identical crystallographic structure of the two materials, hBN is consistently found to exhibit low fluid slip, while Gr is consistently found to exhibit nearly free slip. In this work, we examine interfacial transport characteristics in classical molecular dynamics simulations of layered Gr and hBN; our models correctly predict the equilibrium structure of the confined water and reproduce the pronounced difference in interfacial characteristics of the two materials. Our computational results allow us to elucidate the static and dynamic molecular contributions to the dramatically different characteristics of these materials, illuminating the fundamental mechanisms at play in confined interfacial transport processes.