Graphene hybrid colloidal crystal arrays with photo-controllable structural colors†
An intelligent structural color hydrogel with photo-controllable capability was developed by adding graphene oxide (GO) into colloidal particle solutions. The high charge characteristic of GO could significantly enhance the electrostatic repulsion effect between adjacent particles and promote the ordered assembly of the colloidal particles. The resultant colloidal crystal arrays (CCAs) with a small amount of GO additive were imparted with vivid angle-dependent structural colors due to the enhanced photon absorption of the hybrid materials, whereas their structural colors became dull and angle-independent with a high GO concentration, which contributes to the isotropic short-range ordered CAA nanostructures. It was demonstrated that the GO hybrid structural color hydrogels with temperature-sensitive polymer components featured photo-responsive properties, which provided remotely controllable dynamic structural colors for different patterns. These features of the GO hybrid structural color hydrogels make them promising for the applications of anti-counterfeiting barcode and other related fields.