Fabrication of a Transparent Anti-stain Thin Film Using an Atmospheric Pressure Cold Plasma Deposition System

¹ Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan
² Kagawa National College of Technology, Chokushi-cho, Takamatsu, Kagawa 761-8058, Japan

Abstract

Recently, outdoor-constructed solar panels have a problem such as power generation efficiency is reduced by the face plate dirt. On the other hand, electronic touch panels have a problem such as deterioration of visibility of the screen by finger grease stain. To solve these problems, we need to fabricate the anti-stain surfaces which have superhydrophobic and oil-repellent abilities without spoiling the transparency of the transparent substrate. In this study, we fabricated lotus leaves like surface on a glass substrate. Firstly, SiO₂ particles of ca. 100 nm diameter were arranged on the glass substrates. Secondly, to obtain the fractal-like structure (ultra-micro-rough structure) on the surface, ZnO thin film having a columnar structure was fabricated on the SiO₂ particles by using an atmospheric pressure cold plasma deposition system. By using these processes, the ZnO columns formed radiantly on the spherical surface of the SiO₂ particles. Furthermore, without spoiling the ultra-micro-rough structure, a transparent anti-stain monolayer with low surface energy was prepared by using a chemical adsorption technique onto the surface. Average value of the water droplet contact angles of the samples fabricated was 151.8 deg. Field emission scanning electron microscope (FE-SEM) observation reviled that this sample has a raspberry structure in which columnar structure has grown radially on the SiO₂ particles.