Sprecher
Beschreibung
Ultra-low-crosslinked (ULC) PNIPAM microgels were complexed with tannic acid through supramolecular hydrogen-bond interactions. Rather than simply introducing additional crosslinks, tannic acid triggers a dramatic restructuring of the initially homogeneous and highly deformable microgels. The particles transform into a kinetically trapped core–shell architecture characterized by a depleted core and a dense outer shell, yielding a supramolecular capsule-like morphology. This structural transition is evidenced by scattering and electron microscopy experiments. Supported by molecular dynamics simulations, we demonstrate that the strong affinity of tannic acid for PNIPAM drives and stabilizes this nonequilibrium restructuring, providing a molecular-level explanation for the observed morphology. More broadly, the resulting architectures provide a sensitive structural readout of polymer–guest affinity, opening new opportunities for probing interactions in ultrasoft polymer networks and for the development of smart supramolecular capsules. As a proof of concept, we further demonstrate the encapsulation of polycationic antimicrobial peptides within the microgels, followed by tannic-acid-induced capsule formation, illustrating how supramolecular restructuring can be exploited to trap and retain functional cargo within soft colloidal carriers.