Preparation and characterization of hydrophobic organic-inorganic composite thin films of PMMA/SiO2/TiO2 with low friction coefficient

Organic-inorganic polymethacrylate (PMMA)/SiO2/TiO2 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 C8F17SO2NHC3H6Si(OCH3)(3) (trade name: FC-922) effectively increases the hydrophobicity of the film with a contact angle for water of more than 100degrees. 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. (C) 2003 Elsevier B.V. All rights reserved.