Iridescent coating of graphene oxide on various substrates

Two-dimensional nanomaterials have been incorporated into coating layers for exceptional properties in mechanic toughness, electronics, thermology and optics . Graphene oxide (GO), however, was greatly hindered by its strong adsorption within visible wavelength and hereby the intrinsic dark color at the solid state. Herein, we found a unique aqueous mixture of GO containing sodium dodecyl sulfate and l -ascorbic acid. It enabled to produce iridescent coating layers with tunable thickness of 0.3–50 μm on both hydrophilic and hydrophobic substrates ( e.g., glass, aluminum foil, polytetrafluoroethylene), through brushing, liquid-casting, dipping and writing. Their iridescence could be further tuned by incorporating MXene nanosheets . And their mechanical properties could be enhanced by certain synthetic polymers ( e.g., polyvinyl alcohol and polyethylene glycol). Their sensitivity to heat, laser and water also benefited to pattern the coating layers. Furthermore, by controlling laser intensity, the domain color could be changed ( e.g., green to blue). Thus, this study may pave a new pathway of producing iridescent coatings of graphene oxide in a large scale for practical applications.