Self‐Assembled Chiral Film Based on Melanin Polymers

Abstract

ABSTRACTChirality plays a fundamental role in natural phenomena, yet its manifestation on solid surfaces remains relatively unexplored. In this study, we investigate the formation of chiroptical melanin‐based self‐assembled films on quartz substrates, leveraging mussel‐inspired surface chemistry. Water‐soluble porphyrins serve as molecular synthons, facilitating the spontaneous formation of hetero‐aggregates in phosphate‐buffered saline containing L‐ or D‐DOPA. Spectroscopic analysis reveals chiral transfer from DOPA enantiomers to porphyrin hetero‐aggregates, followed by the disruption of these latter and subsequent generation of chiral melanin structures in solution. Quartz substrates inserted into these solutions spontaneously accumulate homogeneous melanin‐like films over days, demonstrating the feasibility of self‐assembly. The resulting films exhibit characteristic UV/Vis and CD spectra, with distinct signals indicating successful chiral induction. Interestingly, the AFM characterizations reveal a distinct surface morphology, and in addition, some thermal and mechanical properties have been taken into account. Overall, this study sheds light on the formation, stability, and chiroptical properties of melanin‐based films, paving the way for their application in various fields.