Assembly of self-cleaning perfluoroalkyl coating on separation membrane surface

Most membrane-based separation technologies for water treatment are severely limited by fouling-induced flux decline. Herein, a self-cleaning coating with weak chargeability was achieved by assembly of perfluorooctane sulfonate (PFOS) and polyethyleneimine (PEI) on hydrolyzed polyacrylonitrile (HPAN) membrane. The -NH₃⁺ endowed the membrane with hydrophilicity, thus introducing fouling-resistance property. The -CF_X in the coating endowed the ultrafiltration membrane with low surface energy (23.3 mJ/m²), thus introducing fouling-release property. Besides, a weakly-charged surface (8.4 mV) was obtained by the charge counteract between -SO₃⁻ on PFOS and -NH₃⁺ on PEI, which further intensified the fouling-release property. The resultant membrane with such a self-cleaning coating exhibited superior antifouling property during oil/water emulsion and bovine serum albumin solution filtration. This facile assembly method may open up a new avenue towards engineering antifouling membrane surface for efficient water treatment.