Ultrasonic dispersion and activation of TiO2 nanoparticles and its effect on bacterial inhibition in EVA films

Abstract By incorporating titanium dioxide (TiO 2 ) nanoparticles, assisted by ultrasound, it was possible to confer antibacterial properties to an ethylene- co -vinyl acetate (EVA) matrix. A systematic study of the ultrasonic process was performed to determine whether or not the sonication parameters have a significant effect on the nanoparticles dispersion and therefore, on the composite antibacterial property. Scanning electron microscopy showed a significant difference in the TiO 2 agglomerate size when sonication was applied instead of mechanical dispersion. In addition, the TiO 2 nanoparticles efficiency to inhibit bacterial growth was demonstrated by comparing the measurements of colony forming units as a function of the dispersion treatment. It was found that the combination of 60% pulse and 60% amplitude were the best conditions to reduce Escherichia coli growth.