Balancing the Hydrophilic and Hydrophobic Moieties on Carbon Dots to Act as an Efficient Particle Surfactant

Various surface-active nanoparticles have been extensively investigated to achieve enhanced surface activity and unique functionalities. Herein, we developed a facile one-step solvothermal synthesis method for carbon dots (CDs) as a novel surfactant, using plant oil precursors. Optimization experiments elucidated that the carbonization temperature significantly influences the surface states of the CDs. Importantly, the balance of hydrophilic and hydrophobic moieties on the CDs surface endowed them with superior surface activity and emulsion performance. These excellent surfactant-like properties allowed CDs to achieve high efficiency in removing dirt oil comparable to that of traditional surfactants. Due to the strong synergistic effect, combination of CDs with cetyltrimethylammonium bromide not only decreased the surface tension at a lower critical micelle concentration but also reduced the required amount of CDs for oil removal. This mixture demonstrated effective oil dirt removal from four common substrates, regardless of the treatment modes employed, thereby highlighting the significant potential for practical applications in daily oil dirt removal.