Influence of UV Radiation on Surface Characteristics and Friction Properties of FOTS SAMs

1H,1H,2H,2H-Perfluorooctyltrichlorosilane (FOTS) self-assembled monolayers (SAMs) were deposited on silicon substrate by self-assembled technique. Ultraviolet radiation treatment on FOTS SAMs was conducted. By using contact angle meter, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and UMT-2 tribometer, surface characteristics and tribological properties were evaluated. The experimental results show that the contact angle of distilled water on FOTS SAMs was 109°. The formation of hydrophilic -COOH group due to the oxidation of carbon species by O₃ during UV radiation made low contact angle and rough surface. FOTS SAMs with and without radiation had better tribolgical behavior than silicon substrate in micro loads. UV radiation increased friction coefficient of FOTS SAMs and accelerated wear because surface structure and wettability were modified by UV radiation.