Preparation and characterization of hydrophobic organic–inorganic composite thin films of PMMA/SiO 2/TiO 2 with low friction coefficient

Abstract

Organic–inorganic polymethacrylate (PMMA)/SiO 2/TiO 2 composite thin films with controlled thickness and hydrophobicity have been synthesized. The precursor solution of hybrid systems based on 3-trimethoxysilyl propyl methacrylate (TMSM), tetramethylorthosilicate (TMOS), methyl methacrylate (MMA), and tetrabutyl titanate (TBT) were prepared by sol–gel processes. The in situ derivatization of the precursor solution by perfluoroalkylsulfonyl alkyl triakoxy silane C 8F 17SO 2NHC 3H 6Si(OCH 3) 3 (trade name: FC-922) effectively increases the hydrophobicity of the film with a contact angle for water of more than 100°. The structure and properties of the hybrid composite thin film were investigated using TG/DTA, FT-IR, XRD, XPS, and AFM. The thickness of the thin film was less than 120 nm which was measured by cross-sectional scanning electron microscopy. The tribological behavior of the thin film was examined. The friction coefficient of the film prepared is very low (0.09–0.11), and the anti-wear behavior is good, with a lack of failure even after 8000 sliding passes. These films are meeting practical lubricant and protection process requirements, including low processing temperature, high thermal stability, and reliable mechanical properties.