2-Dimensional Clay/Reduced Graphene Oxide Ordered Heterostructures Dispersible in Water via a One-Step Hydrothermal Route

A facile and green method for trapping the hydrophobic reduced graphene oxide between the hydrophilic Kunipia F layers in order to attain stable aqueous dispersions of reduced graphene oxide is described. Initially stable aqueous dispersions of hydrophilic clay intercalated with hydrophilic graphene oxide sheets were formed providing well-organized heterostructures, as it was revealed by scanning electron microscopy images. These structures were preserved in the product obtained after hydrothermal treatment where the hydrophilic graphene oxide was converted to hydrophobic reduced graphene oxide. Ultraviolet measurements revealed the aforementioned conversion which was accompanied by a characteristic change in color from yellow-brown to black in the corresponding aqueous dispersions of these hybrids before and after hydrothermal treatment. The stability of these homogeneous dispersions was confirmed by Zeta Potential measurements implying interactions both in cases of graphene oxide and reduced graphene oxide with clay sheets that made feasible the effective interstratification of graphene-clay layered materials. In these stable dispersions chemistry in aqueous environment could be fully utilized making possible their incorporation e.g., as fillers to hydrophilic polymeric matrices extending thus the limits of application.