Architected C70/Graphene Oxide Composites Prepared under Continuous Flow in a Vortex Fluidic Device: Implications for Supercapacitors

Grapheneoxide (GO) and fullerene C-70 form architected-likeC(70)/GO structures in high yield under continuous flow processingin a vortex fluidic device (VFD). The composite material forms withinhigh-shear regimes in the thin film microfluidic platform, in theabsence of surfactants, and indeed in the absence of any auxiliarysubstances. The structures form on intense micromixing of an o-xylene solution of C-70 and a colloidal suspensionof GO in dimethylformamide (DMF) at ambient conditions, with the liquidsdelivered through jet feeds at the same flow rate to the hemisphericalbase of the rapidly rotating quartz tube in the VFD, which is tiltedat 45 degrees. The particle sizes range from 0.5 to 3 mu m, withtheir structure and properties explored using scanning electron microscopy,transmission electron microscopy, thermogravimetric analysis, X-raypowder diffraction, and Raman spectroscopy. The mechanism of formationof the architected-like structures is consistent with the generalmodel of fluid flow in the VFD and arises from localized high-sheartemperature regimes driving desolvation as the nucleation and growthstep for crystallizing the fullerene component, which are then cappedwith GO.