Amplification of Asymmetry via Structural Transitions in Supramolecular Polymer–Surfactant Coassemblies
Freek V. de Graaf, Christian Zoister, Boris Schade, Tarek Hilal, Xianwen Lou, Stefan Wijker, Sandra M. C. Schoenmakers, Ghislaine Vantomme, Rainer Haag, Abhishek K. Singh, E. W. Meijer
Abstract
Asymmetric structures are widespread in nature and essential for life and biointeractive materials. Although nature uniformly operates with homochirality, the hierarchical control of asymmetry in synthetic, water-soluble molecular systems is still underexplored. In this work, we present the amplification of helical asymmetry of benzene-1,3,5-tricarboxamide (BTA) supramolecular polymers by coassembly with homochiral nonionic surfactants. For these mixtures, a strong amplification of asymmetry was observed from the surfactant's molecular chirality to a preferred helicity of the coassembled polymers. This amplification showed maxima at identical stoichiometric ratios for structurally distinct chiral surfactants, demonstrating the similarity of the coassembly mechanism. Notably, the surfactant-induced asymmetry was completely overridden by the introduction of stereogenic centers into the BTA structure, emphasizing the subtlety of the amplification process. Using a combination of spectroscopy and microscopy, we found that surfactants coassemble with the supramolecular polymers to change fiber morphology from racemic double helices to single helices with a preferred handedness. Furthermore, the coassemblies showed a unique combination of structures and dynamics. Our results elucidate the consequences of supramolecular polymer-surfactant coassembly, offering valuable insights into the resulting asymmetric structures.