Preparation and Tribological Properties of Dual Self-assembled Monolayers/Ionic Liquids Composite Lubricating Films

Combining self-assembly technology and spray painting method, the dual self-assembled monolayers/Ionic liquids composite lubrication films (DA-LA-ILs), which including N-3-(Trimethoxysilyl)propyl ethylenediamine(DA), Lauroyl Chloricle(LA) and 1-Dodecyl-3-Methylimidazolium Hexafluorophosphate Ionic liquids (ILS), were prepared on silicon (Si) substrates. The water contact angle meter, Fourier transform infrared spectroscopy and atomic force microscope were used to characterize the wettability the molecular components, microscopic morphologies and microscale adhesion behaviors of the films. The tribological properties of the films were analyzed by a ball-on-plate tribolometer. The investigation reveals that the adhesion properties of Si surface were effectively improved after being modified by the DA-LA-ILs composite lubrication film. Meanwhile, compared with the DA-LA dual sel-assembled monolayers and ILs modified Si substrate, the composite lubricating film showed the best friction-reduction and wear-resistance properties. The results provide theoretical foundation and experimental basis for the applications of DA-LA-ILs composite lubricating film to reduce the adhesion between micro surfaces and improved wear resistance in micro-electro mechanical systems.