Bio-Inspired Self-Adhesive Bright Non-iridescent Graphene Pigments

Owing to the unique features of angle independence and wide-angle display, non-iridescent materials have attracted increasing interest in coating, decoration, and anti-counterfeiting. However, there are still some defects that limit their applications, such as relatively pale colors and suboptimal stability. Inspired by mussels' super-adhesivity and feathers' brightness, we present a graphene-doped non-iridescent pigment to overcome the aforementioned limitations. The elementary unit of the pigments is polydopamine-adhered multi-shell graphene oxide-encapsulated silica nanoparticles. These nanoparticles form into microspheres after simple spraying, and the obtained angle-independent patterns are imparted with higher color saturation and excellent self-adhesivity compared with traditional non-iridescent materials. Moreover, our pigments can also be employed as templates for negative replication, and the resultant inverse opal hydrogels are endowed with the same amorphous features and even some additional functions such as photothermal responsiveness and self-healing capacity. These features indicate promising prospects for our designed pigments.