Plasma deposition of silver nanoparticles on ultrafiltration membranes: antibacterial and antibiofouling properties

Abstract

tA novel and versatile plasma reactor was used to modify polyethersulphone commercial membranes. The equipmentwas applied to: (i) functionalize the membranes with low-temperature plasmas, (ii) deposit a film of poly(methylmethacrylate) (PMMA) by Plasma Enhanced Chemical Vapor Deposition (PECVD) and, (iii) deposit silver nanopar-ticles (SNP) by gas flow sputtering. Each modification process was performed in the same reactor consecutively,without exposure of the membranes to atmospheric air. Scanning electron microscopy and transmission electronmicroscopy were used to characterize the particles and modified membranes. SNP are evenly distributed on the mem-brane surface. Particle fixation and transport inside membranes were assessed before- and after-washing assays byX-ray photoelectron spectroscopy depth profiling analysis. PMMA addition improved SNP fixation. Plasma-treatedmembranes showed higher hydrophilicity. Anti-biofouling activity was successfully achieved against Gram-positive(Enterococcus faecalis) and -negative (Salmonella) Typhimurium bacteria. Therefore, disinfection by ultrafiltrationshowed substantial resistance to biofouling. The post-synthesis functionalization process developed provides a moreefficient fabrication route for anti-biofouling and anti-bacterial membranes used in the water treatment field. To thebest of our knowledge, this is the first report of a gas phase condensation process combined with a PECVD procedurein order to deposit SNP on commercial membranes to inhibit biofouling formation.