title: Covalent Functionalization of Fluorinated Graphene and Subsequent Application as Water-based Lubricant Additive.
abstract: Although the fluorinated graphene (FG) possesses numerous excellent properties, it can not be really applied in aqueous environments due to its high hydrophobicity. Therefore, how to achieve hydrophilic FG is a challenge. Here, a method of solvent-free urea melt synthesis is developed to prepare the hydrophilic urea-modified FG (UFG). Some characterizations via transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transfer infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermo gravimetric analysis (TGA) demonstrate that the urea molecules can covalently functionalize the FG and the hydrophilic UFG can be prepared. According to the tribological tests run on an optimal-SRV-I reciprocation friction tester, it can be found that the antiwear ability of water can be largely improved by adding the appropriate UFG. When the concentration of UFG aqueous dispersion is 1 mg/mL, the sample of UFG-1 has the best antiwear ability with a 64.4% decrease of wear rate compared with that of the pure water (UFG-0), demonstrating the prepared UFG can be used as a novel and effective water-based lubricant additive.
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, People's Republic of China.|University of Chinese Academy of Sciences , Beijing 100080, People's Republic of China.
authors.forename: Xiangyuan
authors.initials: X
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, People's Republic of China.
authors.forename: Limin
authors.initials: L
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, People's Republic of China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, People's Republic of China.
authors.forename: Jinqing
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, People's Republic of China.
authors.forename: Honggang
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, People's Republic of China.
authors.forename: Shengrong
authors.initials: S
authors.lastname: Yang
keywords: fluorinated graphene (FG); friction; functionalization; hydrophilicity; water-based lubricant additive; wear