Chirality Directs Coacervate Formation, Structure, and Function

Chirality governs molecular recognition and assembly, yet its influence on condensed soft phases remains unknown. We show that stereochemical configuration directly regulates phase separation and internal organization in small-molecule coacervates formed by diphenylalanine derivatives. Homochiral peptides undergo coacervation at lower concentrations to form compact, ordered droplets stabilized by hydrogen bonding and π-π stacking, whereas heterochiral combinations yield more dynamic, permeable condensates. These differences extend to tripeptide systems, revealing a stereochemical control axis that defines droplet order, stability, and molecular selectivity. Achiral molecules partition uniformly across all droplets, but chiral probes exhibit strong stereoselective enrichment in heterochiral coacervates. Together, these results establish stereochemistry as a determinant of packing geometry, mesoscale organization, and selective permeability in peptide-based condensates, revealing a general physical principle by which chirality programs order and function in soft matter.