A series of fluorinated liquid crystal compounds with perfluoroalkyl chains are reported and their properties as lubrication additives are discussed. The structures were characterized by Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), and mass spectrum (MS). The liquid crystalline properties were examined by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), the tribological properties were tested by a universal mechanical tester (UMT), a friction tester, and a 3D optical microscope, and the worn surfaces were analyzed by scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that PAO4 with fluorinated liquid crystals (LCs) led to a significant reduction in friction coefficient (30%) and wear (twice over). And the tribological performance was closely related to mesogenic temperature ranges of liquid crystals. The analysis of EDS and XPS indicated that a protective film can be formed of ferric oxide and ferric fluoride. It can be hypothesized that the tribofllm could avoid the direct contact of the rough material on the metal surface on the metal surface, thus reducing friction and wear.
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