Preparation and tribological behaviour of multiply-alkylated cyclopentane-1H,1H,2H,2H-perfluorodecyltrichlorosilane dual-layer film on diamond-like carbon

Abstract

Hybrid dual-layer film was prepared on diamond-like carbon (DLC) surface by depositing mobile lubricant multiply-alkylated cyclopentane (MAC) on 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane self-assembled monolayers (FDTS-SAMs). The formation of comparatively uniform FDTS-SAMs on DLC surface was verified by static contact angle measurement, X-ray photoelectron spectrometer, and atomic force microscope (AFM). AFM result showed that a high density of regular but discrete nano-scale island-like liquid droplets of MAC were distributed on DLC surface with an interlayer of FDTS-SAMs to form hybrid AC-FDTS dual-layer film. The average diameter and height of MAC droplets on FDTS-SAMs are 30 nm and 35 Å, respectively, and the area covered by MAC droplets is ∼60 per cent. The tribological behaviour of the resulting hybrid film was evaluated on a pin-on-plate test rig using Zdol-2000 film and FDTS-SAMs as reference. The result showed that hybrid MAC-FDTS dual-layer film exhibited the best reducing-friction capability, load-carrying capacity, and durability compared with Zdol-2000 and FDTS-SAMs at applied loads of 50–250 mN. This may be attributed to the self-healing ability of the mobile MAC lubricant to diffuse and cover the damaged or defective areas of the substrates.