Grafted semiconductors on PE-films leading to bacterial inactivation: Synthesis, characterization and mechanism

This study reports the colloidal preparation FeOx, TiO2 and FeOx-TiO2 grafted on polyethylene (PE) films leading to bacterial inactivation. A fast bacterial inactivation was attained by the FeOx-TiO2 compared to the FeOx-PE film due to the interfacial charge transfer (IFCT) FeOx to the lower-lying TiO2 trapped states. A pH-decrease was observed during bacterial inactivation due to the formation of carboxylic acids on the grafted films and the recovery to the initial pH 7 after elimination of the intermediates was followed quantitatively during bacterial inactivation. The potential on the TiO2-PE, FeOx-PE and FeOx-TiO2-PE film surfaces decreased during the bacterial inactivation concomitant with the loss of the cell wall permeability. Different mechanisms for the photo-induced E. coil inactivation for random nanoparticulate FeOx-PE and FeOx-TiO2-PE films are suggested based on the experimental observations reported in this study. During the inactivation of E. coli, the Fe-ions were seen to leach out in amounts