TiO2 thin-films on polymer substrates and their photocatalytic activity

We have developed dip-coating process for TiO2-thin film on polymer substrates (acrylonitrile–butadiene–styrene polymer: ABS, polystyrene: PS). At first, a monodispersed and transparent TiO2 nano-sol solution was prepared by the controlled hydrolysis of titanium iso-propoxide in the presence of acetylacetone and nitric acid catalyst at 80 °C. Powder X-ray diffraction patterns of the dried particles are indicative of crystalline TiO2 with anatase-type structure. According to the XRD and transmission electron microscopy (TEM) studies, the mean particle size was estimated to be ca. 5 nm. The transparent thin films on ABS and PS substrates were fabricated by dip-coating process by changing the processing variables, such as the number of dip-coating and TiO2 concentration in nano-sol solution. Scanning electron microscopic (SEM) analysis for the thin film samples reveals that the acetylacetone-modified TiO2 nano-sol particles are effective for enhancing the interfacial adherence between films and polymeric substrates compared to the unmodified one. Photocatalytic degradation of methylene blue (MB) on the TiO2 thin-films has also been systematically investigated.