The photoinduced hydrophilicity of TiO2/WO3 double layer films was fabricated by using a conventional rf-magnetron sputtering method. The photoinduced hydrophilic reaction of the TiO2 surface was enhanced by the presence of WO3 under the TiO2 layer by irradiation of a 10 W cylindrical fluorescent light bulb. However, when the TiO2 and WO3 layers were separated by an insulating layer, the surface did not appeared high hydrophilic,under the same light bulb. The enhanced photoinduced hydrophilic reaction can be explained by the charge transfer between TiO2 and WO3 layers. It was also demonstrated that visible light passing through the TiO2 layer could excite WO3. Thus, visible light can be used for the hydrophilic reaction in the present TiO2/WO3 system.
WO3, SiO2, and TiO2 films with hydrophilic property are deposited by rf-magnetron sputtering. Their wettability is strongly depends on the presence or absence of the oxygen plasma etching on the glass substrates. The TiO2 film of 50 nm-thick on the plasma etched glass shows a water contact angle (WCA) below 5o which means a super-hydrophilic surface. However, WCA values are gradually degraded when the films are exposed under atmosphere, especially WO3. In order to improve hydrophilic property, the degraded films can be again recovered by UV illumination for 10 sec using UV-light and the TiO2 film shows a super-hydrophilic surface about 3o.
In this paper, we present a novel hydrophilic coating material (Wellture Finetech, Korea) which can be utilized as a coating layer for anti-contamination for electrical and electronic system. The coating material was deposited on 4 inch silicon wafer with several different film thickness. The film thickness was controlled by spin coating speed. After curing of the film, we have scratched by permanent marker to check self-cleaning property of the film. Also we have executed several mechanical tests of the films. As the spin coating speed is increased, the film thickness was thickness was thinned from 230 nm to 125nm. Contact angle of the film lowered from 30° to 12° as the spin coating speed is increased from 700 to 2,500rpm. On permanent marker scratched film surface coated at 1,000 rpm. We have poured regular city water to investigate self cleaning property of the film. The scratches were gradually separated from the film surface due to super-hydrophilicity of the film. Hardness of coated film was 9H measured by ASTM D3363 method. And adhesion of all film was 5B tested by D3359 method. Also, to get exact hardness value of the film, we have utilized a nano-indenter. As spin speed is increased, the hardness of film was increased from 3 Gpa to 5 Gpa.
Effect of O2Plasma Treatment on the Surface Morphology and Characteristics of Poly (imide) to Develop Self-cleaning Industrial Materials In-Sook Kang Journal of the Korean Society of Clothing and Textiles.2012; 36(10): 1117. CrossRef
Effect of Two-step CHF3Plasma Treatment for Poly(imide) and Poly(ethyleneTerephthalate) Pre-treated by O2Plasma on Surface Characteristics In-Sook Kang, Jong-Joo Rha Textile Science and Engineering.2012; 49(5): 314. CrossRef
First
Prev
