Untangling the Diffusion Mechanism of Water in a Heterogeneous Nanochannel

Abstract

Heterogeneous confinement systems attract increasing attention owing to their widespread applications in diverse areas. However, it is still lacking an in-depth understanding of the diffusion mechanism and physical properties of water in the heterogeneous nanochannel through molecular simulations. Here, high-precision TIP4P-BGWT water molecules confined in molybdenum disulfide (MoS₂) and graphene walls are utilized to investigate the influences of variables, i.e., channel height, wettability of walls, charge of MoS₂, and temperature, on the diffusion mechanism and physical properties. The simulation results indicate that the diffusion mechanism is significantly affected by the channel height and temperature but weakly influenced by the wettability of walls. Observable impacts on the physical properties can be observed with the channel height and temperature, but slight impacts are observed with the wettability of walls. Considered variables, excluding charge of MoS₂, remarkably influence density distribution, while limiting mean square displacement at the channel height depends solely upon the effective diffusion distance. It is worth noting that, compared to the homostructure, significant discrepancy in the density distribution can be obtained from the heterogeneous nanochannel due to different solid–liquid interactions. The present study offers a solid foundation for the design of nanodevices, such as nanomembrane, nanosensor, microfluidic chip, etc.