POS2-0502
Photoswitchable Coordination Competition for In-Situ Tunable Damping in Stimuli-Responsive Supramolecular Networks
Topic
S2. High-End Characterization/Polymer Physics/Properties
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Sieun Je (Pusan National University)
Co-Author(s)
Abstract
Adaptively controlling viscoelastic properties across varying mechanical frequencies is a primary objective in the design of next-generation smart damping materials. Although dynamic polymer networks crosslinked via metal–ligand (M–L) coordination offer additionally energy dissipation, their relaxation dynamics typically become fixed by the inherent thermodynamic and kinetic parameters (log K and kd) at the time of network formation. Post-synthetic modulation of the damping frequency strictly requires modifications to the chemical composition, as the established network structure constrains dynamic tuning. Here, we report a supramolecular polymer network in which the energy dissipation frequency window can be controlled in situ through external stimuli. The network consists of an imidazole-functionalized poly(dimethylsiloxane) (PDMS) matrix crosslinked with transition metal ions and physically blended with a photo- and thermo-responsive spiropyran (SP) co-ligand. Upon UV irradiation, SP isomerizes into its zwitterionic merocyanine (MC) form. Because MC exhibits a much stronger metal-binding affinity than imidazole, it outcompetes imidazole for the metal center, triggering a reversible coordination play. Rheological frequency sweeps and relaxation time spectrum (H(τ)) deconvolution show that this molecular transition selectively modulates the relaxation modes associated with the dynamic M–L bonds, while the segmental dynamics of the PDMS backbone remain unaffected. Through light or thermal triggers, the active damping frequency can be shifted by one to two orders of magnitude, offering a practical design strategy for adaptive viscoelastic materials.
