Despite a growing understanding of factors that drive monomer self-assembly to form supramolecular polymers, the effects of aromaticity gain have been largely ignored. Herein, we document the aromaticity gain in two different self-assembly modes of squaramide-based bolaamphiphiles. Importantly, O → S substitution in squaramide synthons resulted in supramolecular polymers with increased fiber flexibility and lower degrees of polymerization. Computations and spectroscopic experiments suggest that the oxo- and thiosquaramide bolaamphiphiles self-assemble into "head-to-tail"versus "stacked"arrangements, respectively. Computed energetic and magnetic criteria of aromaticity reveal that both modes of self-assembly increase the aromatic character of the squaramide synthons, giving rise to stronger intermolecular interactions in the resultant supramolecular polymer structures. These examples suggest that both hydrogen-bonding and stacking interactions can result in increased aromaticity upon self-assembly, highlighting its relevance in monomer design.

Researchers investigated the effect of various (bio)polymeric crosslinkers on the self-assembly process of this reaction-coupled hydrazide-aldehyde gelator into hydrogel materials as a model system. They selected duplex DNA, which acted as a stiff, negatively charged rigid rod below its persistence length ideal for the construction of (nano)materials,[38–40] and compared it against a soft, neutral poly(ethylene glycol) (PEG) polymer of comparable size. Aldehyde moieties were specifically incorporated at the terminal ends of the (bio)polymers to introduce them during the self-assembly of the reaction-coupled network composed another set of (bio)polymers. The researchers also examined the effect of these two crosslinkers on the gelation of the reaction-coupled monomers into hydrogels over several length scales and compared their resultant materials properties.