One-step exfoliation and functionalization of fluorinated graphene sheets from fluoride graphite by ammonia carbonate-assisted solid ball milling

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/oxygen-containing 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.