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One‑step exfoliation and functionalization of fluorinated graphene sheets from fluoride graphite by ammonia carbonate‑assisted solid ball milling Chuanyun Wan1 · Min Ma1

© Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Functionalized fluorinated graphene sheets (FFGS) were formed by ammonia carbonate-assisted solid ball milling method. The exfoliation, defluorination and partial substitution of fluorine of graphite fluoride were occurred during the ball milling process at the presence of ammonia carbonate. Nanosized FGS with few layers (1–2 layers) were successfully produced and partial fluorine atoms were replaced by nitrogen or oxygen elements. The partial replacement of fluorine by amino/oxygencontaining groups makes FFGS own an improved solubility in solvents. The nanosized FFGS as a lubricant additive have an excellent dispersion and stability in lubricant oil. The friction efficient is much lower for the FFGS-doped lubricant oil (0.103 under the load of 196 N) than that of the base oil (0.141). The improved antiwear properties of FFGS-doped lubricant oil indicate that FFGS has a great potential application as lubricant additive in lubrication engineering. The solid ball-milling method offers a promising way for facial, efficient and scalable production of ultrasmall functionalized fluorinated graphene sheets. Keywords  Solid ball milling · Graphite fluoride · Functionalization · Fluorinated graphene sheets

1 Introduction Graphite fluoride (GrF) is a kind of graphite intercalation compounds, in which fluorine atoms are introduced in form of C–F bonds and its C–C bonds transfer from sp2 to sp3 [1–3]. The covalent C–F bands make the surface free energy of graphite fluoride is very low and make GrF exhibit the unique property of water and oil repellency [4]. The excellent lubricant properties are also well-known for this material [5]. Similar to Teflon, fluorographene (FG), is considered to be a 2D counterpart of Teflon and own excellent stability (inert and stable up to 400 °C in air [1]). As one member of the graphene derivatives [1, 6–9], fluorographene exhibits high young’s modulus (100 N m−1), high-quality insulator (> 1012 Ω), high thermal stability and unique optical properties [1–3, 8]. Hence, FG has attracted much attention and has been investigated for a variety of applications * Chuanyun Wan [email protected] 1



School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, China

such as nanocomposites [10], batteries [11], lubricants [1], semiconductors [1, 12, 13] and so on [14–16]. However, a primary prerequisite for the successful application of FG is that FG can be readily prepared and can be compatibility with its operational environment. Hence, exploring a reliable and simple method to produce fluorinated graphene sheets (FGS) and modifying the surface properties of FGS are of particular significance to fully display FG’s properties and to explore its potential applications. The preparation methods of FG can be categorized