Surface engineering of graphene quantum dots and their applications as efficient surfactants

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Graphene quantum dots (GQDs) possess tunable surface properties that influence their integration into hybrid materials.
• Controlling GQD surface chemistry is crucial for optimizing their performance in various applications.

Purpose of the Study:

• To develop a facile method for systematic control over GQD surface properties.
• To investigate the impact of surface modification on GQD behavior in emulsions and dispersions.
• To explore the potential of modified GQDs as fluorescent surfactants.

Main Methods:

• One-step surface modification of hydrophilic GQDs with varying amounts of hydrophobic hexylamine.
• Density functional theory (DFT) simulations to predict GQD geometry.
• Experimental validation of GQD surfactant capabilities in Pickering emulsions and mini-emulsion polymerization.
• Assessment of GQD dispersion in liquid-solid systems (graphite in methanol).

Main Results:

• Precisely controlled surface modification of GQDs achieved by adjusting hexylamine grafting.
• Surface-modified GQDs demonstrated effective stabilization of oil-in-water Pickering emulsions.
• Successful application in mini-emulsion polymerization for submicron-sized colloidal particles.
• Tailored dispersion of graphite in methanol using GQD surfactants.
• Resulting particles exhibited fluorescence from the GQDs.

Conclusions:

• The developed method allows for systematic tuning of GQD surface properties.
• Surface-modified GQDs function as versatile and effective surfactants.
• The fluorescence of GQDs in the modified particles opens avenues for sensing and imaging applications.