Novel insights into the field-flow fractionation characterization and their electrical properties of graphene oxide and reduced graphene oxide materials

Abstract The flow-method physicochemical characterization of graphene-based materials (GBMs) has potential in many fields, such as the engineering of sensors, superconductors and energy storage devices. In this work, an asymmetrical flow field-flow fractionation (AF4) method was developed for characterizing the size and size distribution of graphene oxide (GO) and reduced graphene oxide (rGO), respectively. Notably, stable particle size distributions (PSDs) and sizes in the nanoscale range ( r g GO = 10 to 21 nm; r g rGO = 10 to 54 nm) were observed for both materials, with complementary dynamic light scattering (DLS) measurements ( r h GO = 587.2 ± 68.0 nm; r h rGO = 1170.1 ± 168.8 nm) performed. Additionally, interfacial conductivity analyses between the GBMs and the applied separation solvent performed by electrochemical impedance spectroscopy (EIS) ( R ct (GCE/GO) = 3.81 kΩ; R ct (GCE/rGO) = 15.32 kΩ) revealed different electroactive behaviours of each GBM. Finally, subsequent zeta potential experiments for GO and rGO demonstrated good colloidal stabilities (ζ GO = -45.2 ± 3.3 mV; ζ rGO = -47.5 ± 0.9 mV), as supported by the successful fractionation of the GBMs by AF4. These findings contribute to the standardized separation-based characterization of GBMs as widely applied nanomaterials in materials science applications. Graphical Abstract