Abstract
It is well known that photo-induced hydrophilic conversion on titania can be utilized for self-cleaning coatings. In this case, not only water wettability but also oil wettability is changed due to the photo-induced reaction. For practical applications, oil wettability is more important than water wettability. However photo-induced oil wettability change has not been studied as well as water wettability. In this study, we have prepared titania thin film by rf-magnetron sputtering changing deposition conditions to evaluate photo-induced oil wettability change. The sample prepared by optimized fabrication condition exhibited slightly oreophobic(20 degree) and highly hydrophilic surface(0 degree) after enough UV illumination. The other samples exhibited no hydrophilic conversions or just exhibited highly hydrophilic conversion without any oil wettability change. The microstructures of these samples are analyzed and the relationship between the microstructure and the type of photo-induced wettability conversion is discussed.
