Codeposition of catechol–polyethyleneimine followed by interfacial polymerization for nanofiltration membranes with enhanced stability

ABSTRACT Thin‐film composite (TFC) nanofiltration (NF) membranes were fabricated via the codeposition of catechol (CCh) and polyethyleneimine (PEI) followed by subsequent interfacial polymerization with trimesoyl chloride (TMC) on the surface of polysulfone ultrafiltration substrates. The detailed structures and surface properties were characterized by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, ζ potential analysis, and water contact angle measurement. The surface properties, including the roughness, hydrophilicity, surface potential, and NF performances, were facilely tuned through variation of the codeposition time of CCh–PEI for the prepared TFC membranes. The optimized membrane achieved a high rejection (ca. 93%) of MgCl 2 with a flux of around 31 L m −2 h −1 under 0.7 MPa. The results also reveal that the codeposition process endowed the final membranes with much better structural stability in alcohol and improved chlorine resistance compared to commonly interfacial polymerized ones with PEI and TMC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45422.