Fabrication and characterization of superhydrophilic and antibacterial surfaces by silver nanoparticle self-assembly

A superhydrophilic and antibacterial surface with silver nanoparticles (AgNPs) was fabricated on the blend membranes of poly(vinylidene fluoride) (PVDF) and poly(styrene-co-maleic anhydride) (SMA). The PVDF/SMA blend membranes were surface-modified firstly by coating polydopamine (PDA) in aqueous solution for 24 h. Subsequently, AgNPs were immobilized in situ. Lastly, the AgNP-loaded membranes were second coating PDA. Scanning electronic microscopy (SEM) was carried out to characterize both the micro- and nanoscale hierarchical structures. The results of X-ray photoelectron spectroscopy (XPS) indicated that metallic silver was formed and more Ag loaded might be apt to deposit more PDA during the second coating PDA procedure. The membrane surface hydrophilicity was characterized by water contact angle measurement; AgNPs and PDA had provided an excellent hydrophilicity. Meanwhile, AgNPs imparted outstanding antibacterial activity to the modified membranes which was confirmed by halo zone test. All of the results demonstrated that the modified surface possessed superhydrophilic and excellent antibacterial properties.