Development of Transparent Super Water-repellent Films by Composing Surface Fine Structure

本研究旨在建立一种控制等离子体CVD工艺中疏水膜表面形貌和化学键合状态的方法，并开发一种存款透明，采用红外反射吸收光谱（IRRAS）技术，成功地实现了红外吸收光谱的原位测量。在80度的入射角下，使用与傅里叶变换红外光谱仪（FTIR）结合的RF等离子体CVD系统。特别地，选择p偏振IR光导致高灵敏度的测量。我们甚至可以得到单层有机硅分子的红外光谱。通过这种方法，我们建立了一种真实的实时控制薄膜化学键合状态的沉积技术，并推测由于形成了疏水的Si-OH基团，氧与氧的混合气体不能合成超疏水薄膜。然而，我们清楚地表明，在相对较高的总压力下，在150-200 Pa的范围内，用氧气的混合物可以实现超拒水性。从该结果，可以预期形成具有硬度的防水膜。该膜具有超拒水性，虽然它们包括Si-OH官能团。用环境扫描电镜观察了其拒水性。即使对μm大小的水滴，接触角也大于150 °。

This research project aimed at an establishment of a method to control both the surface morphology and the chemical bonding states of the water-repellent films in plasma CVD processes and at a development of a technique ton deposit transparent, hard and super water-repellent films at low temperature over wide area.We succeeded in in-situ measurement of infrared (IR) absorption spectra by infrared reflection absorption spectroscopy (IRRAS) at an incident angle of 80 degree using an rf plasma CVD system combined with a Fourier-transform infrared spectrometer (FTIR). Especially, selecting p-polarized IR light lead to measurement at a high sensitivity. We could obtain IR spectra even for a monolayer of organsilicon molecules. By means of this method, we established a deposition technique to control the chemical bonding states of the films in real time.It has been supposed that super water-repellent films cannot be synthesized with mixture of an oxygen has gas because of formation of hydrophobic Si-OH groups. We made clear, however, that super water repellency can be realized at relatively higher total pressure, in the range of 150-200 Pa, with the mixture of oxygen. From this result, it can be expected that the formation of water-repellent films with hardness. The films have super water-repellency although they include Si-OH functional groups. The reason has not been elucidated and can be an interesting research object.The water repellency was observed by means of environmental scanning electron microscope. The contact angle was over 150 degree even for the water drops in μm size.