Polyamide nanofilms synthesized by a sequential process of blade coating-spraying-interfacial polymerization toward reverse osmosis

•Polyamide nanofilms around 10 nm are facilely synthesized by a scalable process.•A sequential process of coating-spraying-interfacial polymerization is developed.•Organic solvent consumption reduces by 99 % compared with conventional process.•The polyamide nanofilms represent high performance as desalination membranes.