High-yield aqueous phase exfoliation of graphene for facile nanocomposite synthesis via emulsion polymerization

• 90+% FLG graphene nanosheets synthesized in aqueous phase via single step.
• Ultrasonication and surfactant concentration optimized to maximize exfoliation.
• Graphene/polystyrene nanocomposite prepared via one-pot emulsion polymerization.
• Characterizations include UV–vis, TEM, Raman, XRD, FTIR, TGA, EIS, CV.
• Composite potential applications target sensing and catalysis.

Aqueous phase exfoliation was developed for producing high-yield graphene nanosheets from expanded graphite (EG). The process included ultrasonication with sodium dodecyl sulfate (SDS) emulsion in aqueous phase. The high throughput exfoliation process was characterized by UV–vis spectroscopy, transmission electron microscopy (TEM) and electrical impedance spectroscopy (EIS). Controlled sonication experiments revealed that optimum exfoliation corresponds to maxima in UV–vis spectra. TEM results showed that the exfoliated graphene comprised nanoflakes having ⩽5 layers (∼60%) and ⩽10 layers for 90% of the product. The potential use of this highly dispersed graphene was demonstrated by one-pot synthesis of graphene/polymer composite via in situ emulsion polymerization with styrene. The integrated role of SDS included adsorption and exfoliation of graphite, dispersion of graphene produced and assisting with micelle formation in emulsion. The high surface area graphene nanosheets as dispersed phase in polymeric nanocomposites showed significant improvement in thermal stability and electrical conductivity.

Figure optionsDownload high-quality image (81 K)Download as PowerPoint slide