Water Flow through Interlayer Channels of Two-Dimensional Materials with Various Hydrophilicities

Water transport through laminated membranes composed of two-dimensional (2D) materials has gained considerable attention because of their great potential in filtration and separation applications. However, water transport between interlayers formed by 2D materials cannot be comprehensively described by traditional transport theory because different 2D materials have varying hydrophilicity, which strongly affects water transport. Herein, we build interlayer channels formed by 2D sheets with various hydrophilicities and investigate the pressure-driven water transport via nonequilibrium molecular dynamics simulations. The influence of channel hydrophilicity on water transport is dominant, especially at the nanoscale. To model the water-transport phenomena through channels with various hydrophilicities, we define a new slip length to derive the appropriate equation. By two methods of calculating the slip length based on the simulation results, we validate our derived equation, which predicts the water flux in interlayer channels with a large range of hydrophilicities from relatively hydrophobic (large slip lengths) to extremely hydrophilic (negative slip lengths). This work deepens the understanding of water transport through interlayer channels and assists in the design of 2D material membranes for water treatment.