Polycondensation-Involved Melanin-like Polymers for Enhanced Solar Energy Utilization

Abstract

Polydopamine (PDA) and poly(5,6-dihydroxyindole) (PDHI), both typical representatives of melanin-like polymers, are emerging as promising kinds of photothermal functional materials with a similar polymeric structure. However, the chaos of the microstructure formed by free radical polymerization of monomers still hinders the efficient regulation of their photothermal performances. Herein, we introduced condensation polymerization between aldehydes and the 5,6-dihydroxyindole (DHI) monomer during the free radical polymerization process to construct more D–A pairs, which can regulate the energy structures and reduce the optical band gaps within the macromolecules. In this way, a series of PDHI nanoparticles (NPs) with enhanced light absorption of visible light and photothermal properties were successfully prepared and were used for solar power generation and water desalination with 91.8% evaporation efficiency. It was believed that this work could provide new opportunities for the structure–function tailoring of bioinspired materials and further expand their applications for high-efficiency solar energy utilization.