Miniemulsion polymerization using carboxylated graphene quantum dots as surfactants: effects of monomer and initiator type

Abstract

Graphene quantum dots (GQDs) are building blocks of emerging interest for fabrication of polymeric nanocomposite materials with a range of potential applications. In the present work, we have conducted a detailed investigation into the use of carboxylated GQDs as surfactants in aqueous miniemulsion polymerization. The cGQDs were prepared by carbonization of dextrose according to a bottom-up hydrothermal approach. It is demonstrated that cGQDs can satisfactorily stabilize miniemulsions of a variety of vinyl monomers including styrene, acrylates and methacrylates. The nature of the initiation system plays a pivotal role in regards to monomer conversion – the water soluble initiator 2,2′-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA-044) resulted in substantially higher conversions than the oil soluble initiator azobisisobutyronitrile (AIBN). The present results illustrate that these cGQDs have the ability to function as surfactants in miniemulsion polymerization for various vinyl monomer types, which has implications for hybrid nanocomposite nanoparticles and materials synthesis.