Flame aerosol synthesis and thermophoretic deposition of superhydrophilic TiO2 nanoparticle coatings

A highly controllable and tunable technique for the production of thin coating layers of TiO nanoparticles by aerosol flame synthesis and direct thermophoretic deposition is presented. Different flame reactor operations were used to study the effect of particle size and film morphology on coating performances. Particle dimension, crystal phase, coating thickness and optical properties were characterized using Scanning Mobility Particle Sizer, Raman spectroscopy and UV-Vis Absorption. Water contact angle analysis was used to investigate the wetting behavior, showing that titania coating layers are characterized by a high photoinduced hydrophilicity activated by normal solar radiation in standard room illumination conditions. The hydrophilic character was found to be dependent on the dimension of primary particles composing the coating layers. The optimal synthesis conditions have been identified in order to produce a superhydrophilic coating material.