Effect of Structure, Composition, and Micromorphology on the Hydrophobic Property of F-DLC Film

Abstract

Fluorinated diamond-like carbon (F-DLC) films were prepared by radio frequency plasma-enhanced chemical vapor deposition technique with CF4and CH4as source gases under different deposition conditions. The chemical bonding structure and composition of the films were detected by Raman, Fourier transform infrared absorption spectrometry (FTIR), and X-ray photoelectron spectroscopy (XPS) characterization. The micromorphology and surface roughness of the film were observed and analyzed by atomic force microscopy (AFM). The results indicated that all the prepared films presented a diamond-like carbon structure. The relative content of fluorine in the films increased, containing more CF2groups. The ratio of hybrid structure sp3/sp2decreased. The surface roughness of the films increased when the gas flow ratioR(R = CF4/[CH4 + CF4]) or the deposition power increased. The contact angle of water with the surface of the F-DLC film was measured with a static drop-contact angle/surface tension measuring instrument. The hydrophobic property of the F-DLC films was found to be dependent on the sp2structure, fluorine content, and surface roughness of the films. The contact angle increased when the relative content of fluorine in the films and sp2content increased, whereas the contact angle first increased and then decreased with the surface roughness.