Self-Cleaning Particle Coating with Antireflection Properties

We report here a self-cleaning particle coating with antireflection (AR) properties. The coatings were prepared by (1) depositing SiO2 single-layered particle coatings on polyelectrolyte-modified glass substrates through electrostatic attraction, (2) subsequently depositing another layer of TiO2 nanoparticles through electrostatic attraction, and (3) removing the polymer by calcination at 500 °C. The AR effect of the coatings was studied with transmission spectra collected at normal incidence. The self-cleaning properties of the coatings were studied by the change of the water contact angle on octadodecyldimethylchlorosilane-modified coatings under 1.0 mW cm-2 ultraviolet light. Both the AR and self-cleaning properties of the coatings were dependent on the concentration of colloidal TiO2 solution used in the preparation. However, excellent surface wettability of the coatings for water was obtained, independent of the preparation conditions. The experimental findings are discussed in terms of the special structure of the particle coatings.