Preparation of surface-active carbon dots with fluorocarbon and hydrocarbon hybrid chains via a one-pot solvothermal technique and their characterization and potential applications

Amphiphilic carbon dots (CDs) are new surface-active materials that exhibit several advantages over conventional small surfactants, such as improved stability and reduced toxicity. However, unlike for conventional small surfactants, amphiphilic CDs that simultaneously exhibit excellent surface and interfacial activities have never been achieved. Herein we prepare new amphiphilic CDs with fluorocarbon and hydrocarbon hybrid hydrophobic chains (FH-CDs) using a facile one-pot solvothermal technique. The obtained FH-CDs showed excellent surface and interfacial activities, and reduced the surface tension at critical micelle concentration and the oil-water interfacial tension to 16.7 and 2.2 mN/m, respectively. Comparison with control CDs bearing only non-hybrid hydrophobic chains demonstrated that decorating CDs with fluorocarbon and hydrocarbon hybrid chains contributed to the excellent interfacial activity, while only fluorocarbon chains contributed to good surface activity. The excellent surface and interfacial activities made FH-CDs good emulsifiers for the formation of stable water-in-oil emulsions and for the preparation of relatively uniform polystyrene spheres via emulsion polymerization. Moreover, FH-CD was a good wetting agent, whose aqueous solution could wet numerous different surfaces, including the commonly non-wettable amphiphobic polytetrafluoroethylene.