Dipole Alignment and Layered Flow Structure in Pressure-Driven Water Transport through MoS₂ Membranes

Efficient water transport through nanostructure membranes is essential for advancing filtration and desalination technologies. In this study, we investigate the flow of water through molybdenum disulfide (MoS₂) nanopores of varying diameters using molecular dynamics simulations. The results demonstrate that both pore size and atomic edge composition play crucial roles in regulating water flux, molecular organization, and dipole orientation. Larger pores facilitate the formation of layered water structures and promote edge-accelerated flow, driven by strong electrostatic interactions between water molecules and exposed molybdenum atoms. In narrower pores, confinement and asymmetric edge chemistry induce the ordered alignment of dipoles, thereby enhancing directional transport. Velocity and density maps reveal that pore edges act as active zones, concentrating flow and reducing resistance. Our findings reveal that ordered dipole alignment in subnanometer pores is the fundamental mechanism driving directional water transport. Unlike previous studies focused primarily on desalination, we demonstrate that this molecular orientation is a distinguishing factor that governs flow stability. This discovery suggests that MoS₂ membranes are not only efficient for filtration but also highly promising for nanofluidic sensors, where controlled molecular orientation is critical for dictating electrical signals and improving device sensitivity.