Self-Assembly of Octadecyltrichlorosilane on Graphene Oxide and the Tribological Performances of the Resultant Film

Taking advantage of the condensation between Si-OH of the hydroxylated octadecyltrichlorosilane (OTS) and C-OH on graphene oxide (GO) surface, we grafted OTS onto the GO-based dual-layer film, which was composed of GO outerlayer and (3-aminopropyl)triethoxysilane (APTES) self-assembled underlayer, on a Si substrate. Thus, a hydrophobic trilayer film coded as APTES-GO-OTS was prepared successfully. To confirm the chemical composition, structure, and morphology of the trilayer film, various means including water contact angle measurement, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrometry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) were performed. Moreover, to investigate the tribological performances, the micro- and macrotribological experiments were conducted with AFM and a UMT tribometer. The results showed that the as-prepared trilayer film exhibited low adhesion and greatly reduced the friction force in both the micro- and macroscale. Therefore, such a trilayer film is suitable for an application in the lubrication and protection of nano/microelectromechanical systems (NEMS/MEMS).