A Non-Equilibrium Molecular Dynamics (NEMD) Simulation of the Crosslinked Polyamide Membranein Water Desalination

Reverse osmosis of cross-linked aromatic polyamide (PA) membrane is most successful viable desalination technique. Understanding polymer membrane’s microscopic structure with atomistic resolution and the molecular transfer mechanism such as salt rejection and water permeation across sub-nanopores is essential for the improvement of the structure-function design of polymer membrane. In this study, we established a crosslinked PA membrane by using a hierarchical crosslinking protocol based on full-atom molecular dynamics (MD) simulations. The desalination process in the nonequilibrium steady-state was investigated with the established reliable polymer membrane. Our result shows that, although the pore size distribution does not vary significantly, the increasing pressure difference can facilitate higher water permeability inside the membrane without allowing any ion inside the membrane.