Colorful melanin-inspired pigments

Black color is the most typical feature of natural and synthetic melanins, which results from the complex packing and chemical disorder of the molecular structure within melanins. From nature and beyond nature, breaking through the black color boundary, expanding the scope of inherent functions, and establishing clearer structure-function relationship of melanin is necessary but hard due to the inherent chaos structure caused by random covalent coupling and supramolecular assembly. Herein, starting from melanin-inspired monomers, we chose and assembled typical organic acceptor molecules (TCNB/TCNQ) with melanin-inspired donor molecules to prepare a series of colorful melanin-inspired pigments through the co-crystallization strategy. The resulting colorful melanin-inspired pigments exhibited multiple colors and different rod-like morphologies compared with many melanin-like polymers. Particularly, green DHI/TCNQ powder presented excellent photothermal efficiency (∼69.8%) for antibacterial application. This work would provide new structure-function tailoring strategy toward the design of melanin-like polymers with highly ordered structures and desirable properties.