Melanin-Inspired Stable Dispersion of Molten Salt Nanofluids

High Resolution Image Download MS PowerPoint Slide Inorganic molten salt nanofluids have the potential to enable many thermal applications but often suffer from serious detrimental aggregation. Inspired by the melanin-dispersing mechanism, herein, we achieve stable uniform dispersion of various nanoparticles within molten salts through in situ polymerization of l -dopa in the presence of inorganic salt ions. Molten salt cations (Li +, K +, and Na + ) can enhance the polymerization kinetics and modulate the oxidation self-assembly process, promoting the formation of melanin-like poly( l -dopa) (PLD) particles with rough surfaces. The salt ions can form a thick cation–anion alternative charge distribution layer on the surfaces, which enables the long-term homogeneous dispersion of PLD and PLD-coated functional particles within a variety of molten salts. The resultant molten salt nanofluids have shown boosted solar absorptance and enhanced specific heat capacity, which make them suitable for direct harvesting of medium-temperature solar–thermal energy. Such a dispersing strategy can help unlock the door to explore controlled fabrication of highly ionic fluidic functional materials with stable dispersion for a wide range of applications.