One of the most promising applications in nanoscience is the design of new materials to improve water permeability and selectivity of nanoporous membranes. Understanding the molecular architecture behind these fascinating structures and how it impacts the water flow is an intricate but a necessary task. We studied here the water flux through multilayered nanoporous molybdenum disulfide (MLNMoS 2 ) membranes with different nanopore sizes and lengths. Molecular dynamics simulations show that the permeability does not increase with the inverse of the membrane thickness, violating the classical hydrodynamic behavior. The data also reveal that water dynamics is slower than those observed in frictionless carbon nanotubes and multilayer graphene membranes, which we explain in terms of an anchor mechanism observed in between layers. We show that the membrane permeability is critically dependent on the nanopore architecture, bringing important insights into the manufacture of new desalination membranes.

In this work, a two dimensional system of polymer grafted nanoparticles is analyzed using largescale Langevin Dymanics simulations. Effective core-softened potentials were obtained for two cases: one where the polymers are free to rotate around the nanoparticle core and a second where the polymers are fixed, with a 45 • angle between them. The use of effective core-softened potentials allow us to explore the complete system phase space. In this way, the P T , T ρ and P ρ phase diagrams for each potential were obtained, with all fluid and solid phases. The phase boundaries were defined analyzing the specific heat at constant pressure, the system mean square displacement, the radial distribution function and the discontinuities in the density-pressure phase diagram. Also, due the competition in the system we have observed the presence of waterlike anomalies, such as the temperature of maximum density -in addition with a tendency of the TMD to move to lower temperatures (negative slope)-and the diffusion anomaly. It was observed different morphologies (stripes, honeycomb, amorphous) for each nanoparticle. We observed that for the fixed polymers case the waterlike anomalies are originated by the competition between the potential characteristic length scales, while for the free to rotate case the anomalies arises due a smaller region of stability in the phase diagram and no competition between the scales was observed.

A significant portion of current desalination techniques rely on porous membranes whose performance is highly dependent on the delicate trade-off between water permeability and ion rejection. At the nanoscale, water and salt transport are governed by the nanopore's geometry and charge distribution. In this Article, we mimicked the reverse osmosis process with MoS 2 nanoporous membranes using molecular dynamics simulations to shed light on how water and ion transport phenomena influence each other and how they are affected by the nanopore's size and charge distribution. We evaluated the system's water flow rate and salt rejection under real and artificially induced pore charge polarizations and different diameters. By manipulating the pore's partial charges while maintaining a fixed geometry, we were able to separate electrostatic contributions from those dependent on pore size. As expected, we found that an increase in the charge polarization of MoS 2 leads to a higher presence of ions inside the nanopores and a lowering of water permeability. We went further by quantifying this behavior and observed a high correlation between the fraction of pore volume occupied by ions and the decrease in water flow, indicating that the mechanism behind its performance is predominantly linked to geometric exclusion of water molecules rather than more complex changes in water structure. We also found intricate results indicating that inside pristine MoS 2 nanopores with a diameter of 1.33 nm, pore size and electrostatic interactions play comparatively important roles in regulating salt rejection, while in smaller pores (0.97 nm diameter), pore diameter dominates over charge distribution. Our results offer insights into the physics governing transport phenomena inside nanopores made of naturally occurring MoS 2 as well as in similar pores made of different materials with differing charge polarizations. We hope that such understanding can help in the design of more efficient desalination membranes.

One of the most promising applications in nanoscience is the design of new materials to improve water permeability and selectivity of nanoporous membranes. Understanding the molecular architecture behind these fascinating structures and how it impacts the water flow is an intricate but necessary task. We studied here, the water flux through multi-layered nanoporous molybdenum disulfide (MLNMoS 2 ) membranes with different nanopore sizes and length. Molecular dynamics simulations show that the permeability do not increase with the inverse of the membrane thickness, violating the classical hydrodynamic behavior. The data also reveals that the water dynamics is slower than that observed in frictionless carbon nanotubes and multi-layer