Molecular Simulations of Reverse Osmosis Aromatic Polyamide Membrane: Mechanical Properties, Desalination, Crosslinking Degree and Monomers’ Isomer States

Reverse osmosis (R) is one of the leading desalination techniques used worldwide. Thin film composite membranes like polyamide (PA) membranes offer advantages in high flux, high rejection to salt and some low molecular weight organics, and stability at higher temperature and over a larger pH range. It is crucial to understand the mechanical properties of crosslinked polyamide membrane and its relationship with its performance in desalination. In this work, we use molecular dynamic simulation to estimate crosslinked polyamide membrane’s mechanical properties (poison ratio and young's modulus), pore size distribution, water permeation and salt rejection capability as a function of crosslinking degree. We also examine the mechanical properties and pore size distribution by varying monomer’s isomer states. The research will be important for future PA membrane experimental synthesis.