Interfacial Polymerization with Electrosprayed Microdroplets: Toward Controllable and Ultrathin Polyamide Membranes

Commercial polyamide membranes for seawater desalination and water purification have low water permeability because of their relatively thick rejection layers. We report a novel interfacial polymerization method for synthesizing ultrathin polyamide layers with a precisely controllable thickness. Monomer solutions of m-phenylenediamine and trimesoyl chloride were electrosprayed into fine microdroplets. The polymerization reaction between microdroplets of different monomers leads to a fine and controllable amount of deposition. We fabricated smooth polyamide layers from 4 nm to several tens of nanometers in thickness, with a growth rate of approximately 1 nm/min. Our study provides a new dimension for the rational design and preparation of ultrathin polyamide membranes with tunable separation properties.