TIO2 nanoparticle coatings with advanced antibacterial and hydrophilic properties prepared by flame aerosol synthesis and thermophoretic deposition

The production of thin coatings of TiO2 nanoparticles by aerosol flame synthesis and direct thermophoretic deposition is presented. Three different flame reactor configurations were designed in order to study the effect of particle size and film morphology on the performances of the coatings. Particle dimension, crystal phase and surface morphology were characterized using differential mobility analysis, Raman spectroscopy and atomic force microscopy, respectively. The wetting behavior was investigated by water contact angle analysis, showing that titania coatings are characterized by a high photoinduced hydrophilicity. Measurements of the inhibition of Staphylococcus aureus biofilm formation revealed a high antibacterial activity from TiO2 nanoparticle films. Finally, both the hydrophilic character and the bactericidal effects are found to be mainly dependent on the size of primary particles composing the coatings. The optimal synthesis conditions were identified in order to produce a self-cleaning and self-disinfecting coatings material, with a nearly superhydrophilicity and a high antibacterial activity, both activated by ordinary light radiation in standard room illumination conditions.