Polyamide membrane with nanocluster assembly structure for desalination

The structure of the polyamide (PA) nanofilm formed via interfacial polymerization (IP) is vital to the permeance-selectivity of composite membranes. However, it is challenging to control the morphology (e.g., nodules, ridge-and-valley) of the PA nanofilm due to the fast IP kinetics. Herein, we deconstructed the kinetic pathways of IP to probe the structure of the PA nanofilm and demonstrated that (I) the main skeleton of the nanofilm was composed of sub-10 nm nanoclusters; (II) the growth and assembly of nanoclusters shaped the nanofilm structure. Furthermore, we controlled PA nanofilm structure via adjusting the monomers' stoichiometric ratio at the new reaction interface, and the resulted nodules with controlled size and surface characteristics endowed tunable water-salt transport properties. This work offered a detailed understanding of the formation and structure of IP PA nanofilm; these insights can potentially guide the production of high-performance polyamide-based thin-film composite membranes.