Dopamine triggered one step polymerization and codeposition of reactive surfactant on PES membrane surface for antifouling modification

Abstract

The low reactivity and poor compatibility of hydrophobic polymer base with hydrophilic additives poses a challenge for preparation of antifouling ultrafiltration (UF) membrane. In this work, the allyloxy nonylphenoxy propanol polyoxyethylene (SE-10N) ether ammonium sulfate (AHPS), which possessing excellent reactivity and amphiphilicity, was grafted onto PES membrane surface via dopamine triggered one-step polymerization and co-deposition process. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed that AHPS was easily anchored onto the membrane surface with the assistance of dopamine. Field emitting scanning electron microscope (FESEM) and atomic force microscopy (AFM) also demonstrated the formation of a new coating on membrane surface. The modified layer significantly enhanced the hydrophilicity of the ultrafiltration membrane, as confirmed by the decrease of contact angle from 77.2° to 55.8°. As a result, the modified membrane exhibited remarkably improved anti-fouling properties. The static adsorption of bovine albumin (BSA) on membrane surface was decreased from 77.2 to 34.3 µg/cm2. Furthermore, the modified membrane displayed higher flux recovery (95.9%) and fouling reversibility (51.6%) than unmodified membrane (56.7% and 23.0%, respectively). Besides, the modified membrane also showed better structural stability in acid and alkali solutions as compared with pure polydopamine coated membrane. Therefore, this study provided a facile approach for improving the anti-fouling performance of membranes.