Simple methods for dual functional modification of membrane surfaces have been rarely reported but are
highly desirable for the fabrication of antifouling and antibacterial membranes. In this work, we exploit
a multicomponent reaction, Ugi-4CR (Ugi four-component reaction), to prepare novel antifouling and
antibacterial reverse osmosis (RO) membranes. With the aid of the high number of residual carboxyl
groups on a commercial polyamide RO membrane as the anchor and methyl isocyanoacetate as
a component, a hydrophilic macromolecular component, methoxy poly(ethylene glycol) aldehyde
(MPEG-CHO), and an amino-terminated antibacterial component, tris(2-aminoethyl)amine (TAEA) or
sulfamethoxazole (SMZ), were grafted onto the surface in a single step via the Ugi-4CR. The surfaces of
the original and modified membranes were characterized by ATR-FTIR, XPS, TG, WCA, FESEM and AFM
measurements. The antifouling performance was evaluated by cross-flow filtration of protein and
inorganic salt solution. The antibacterial performance was assessed by the shake flask method. The
results show that the Ugi-4CR was successfully conducted on the RO membrane surface and that
MPEG-CHO and the antibacterial agents were successfully grafted. The surface roughness decreased
and surface the hydrophilicity improved upon modification. After 48 h fouling experiments, the obtained
PA-g-PEG/TAEA and PA-g-PEG/SMZ membranes showed obviously lower flux attenuation ratios and
higher flux recovery ratios than the original membrane in both cases when fouled by protein or
inorganic salt. In addition, the bacterial concentrations in the suspensions shook with the modified
membranes were much lower than that of the original membrane. As for the PA-g-PEG/SMZ membrane,
hardly any bacterial growth was seen, even after 24 h culture. In contrast to current multi-step grafting
processes, this work reports a “one pot” procedure with two functional groups grafted simultaneously
under very mild conditions without the use of any catalyst.