Molecular insights into the structure-property relationships of 3D printed polyamide reverse-osmosis membrane for desalination

3D-printing is an emerging method for manufacturing polyamide (PA) reserve osmosis (RO) membranes water treatment and desalination, which can precisely control membrane structural properties, such as thickness, roughness, resolution. However, the synthesis-structure (i.e., degree of cross-linking (DC), m-phenylenediamine/trimesoyl chloride (MPD/TMC) ratio, thickness) to property (permeability water-salt selectivity) relationships these has not been well understood. At same time, a microscopic understanding physical mechanism salt transport needed guide design high-performance 3D-printed improve printing efficiency. Thus, atomic-scale features energetics ions are studied at high pressure PA RO with different DCs MPD/TMC ratios through non-equilibrium molecular dynamics (NEMD) simulations. Factoring in structure rejection ratio pressure-dependent flux, having 3.0:2.0 DC between 80%∼90% attains ideal performance: ions, excellent integrity. Mechanistically, permeability highly cross-linked depends on temporary on-and-off channels that allow molecules jump from one cavity another pressure. In addition, higher pressures cause rapid compaction membranes’ free volume thickness. Membrane failure determined by ratios-dependent compressive yield strength. short, findings provide insights optimizing existing designing next-generation desalination level.