Capillary Flow-Driven, Hierarchical Chiral Self-Assembly of Peptide Nanohelix Arrays

Precise control over the chiral self-assembly of synthetic molecules is of fundamental interest in chemistry and material science. This study reports the hierarchical chiral self-assembly of a ferrocene-modified dipeptide in evaporating droplets. The capillary flows during solvent evaporation changed greatly on the self-assembly of the peptides, leading to the chiral amplification and the formation of well-defined nanohelixes. By changing the initial temperature difference (Δ T ) between the droplets and the substrate, it is possible to control the fluid mechanical effects under two distinct regimes: the “coffee ring” effect caused by outward capillary flow and the Rayleigh convection by buoyancy force. This allows us to control the orientational growth of peptide nanohelixes with their axis parallel or perpendicular to the substrate. The results highlight the vital roles of capillary flow in directing the hierarchical chiral self-assembly of peptides and offer new opportunities for the fabrication of highly ordered chiral nanomaterials.