Supramolecular Polymerization and Morphological Transformation of Dynamic Helical Poly(Phenylacetylene)s via Chain‐End Host–Guest Interactions

ABSTRACT

Integration of dynamic helical polymers with supramolecular polymerization offers a promising strategy for constructing adaptive hierarchical chiral materials. However, the transformation of molecular‐level conformational changes in dynamic helical polymers into structural transformations at the supramolecular level remains unexplored. This study demonstrated the synthesis of supramolecular polymers composed of poly(phenylacetylene) (PPA) chains bearing a pillar[5]arene host unit at one chain end and complementary guest unit at the other. The telechelic PPAs were synthesized using a living polymerization method that enables precise end‐functionalization and subsequently assembled into supramolecular polymers through intermolecular host–guest interactions. To impart stimuli‐responsive behavior, alanine‐derived pendants, capable of forming intramolecular hydrogen bonds, were incorporated into the PPA chains. The resulting supramolecular polymers formed stable assemblies that persisted even after dilution below the concentration required for their initial formation. Solvent‐dependent switching of intramolecular hydrogen bonding induced simultaneous helicity inversion and modulation of the backbone rigidity, leading to pronounced morphological transformations of the supramolecular polymers between cyclic and rigid‐rod architectures, exhibiting viscosities up to 2000 times higher than the control polymer. These results demonstrate that molecular‐level conformational changes in dynamic helical polymers can be translated into higher‐order supramolecular structural transformations, providing a general strategy for designing adaptive hierarchical chiral materials.