Preparation and Investigation of SiO_2/TiO_2 Antireflective Coatings with Self-cleaning and Scratch-resistant Properties

The SiO2 and TiO2 Sol were prepared via Sol-Gel process using tetraethyl orthosilicate(TEOS) and tetrabutyl orthotitanate(TBOT),and the SiO2/TiO2 bilayer coatings with antireflection property were obtained by dip-coating method.The performances of the coatings were analyzed with ultraviolet visible spectrophotometer(UV-Vis),X-ray diffraction(XRD),scanning electron microscope(SEM),atomic force microscope(AFM),ellip-someter and contact angle measurement.The self-cleaning function of coatings was evaluated by means of photo-catalytic degradation of methyl orange in aqueous solution,and scratch-resistant property of the coatings was stud-ied.The results indicate that the peak transmission of the SiO2/TiO2 bilayer coating is up to 97.2% in the visible band,the coating has a flat surface,a dense structure and a low roughness.After illuminated by ultraviolet light for 2h,the SiO2/TiO2 bilayer coating is superhydrophilic with water contact angle up to 0°,and the 5mg/L methyl or-ange can be degraded by 43.6% in 2h.Moreover,the SiO2/TiO2 bilayer coating has an excellent scratch-resistant property.