POS4-0909
Orthogonal Mechanical and Thermal Fluorescence Amplification in a Single Polydiacetylene Platform
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Songseok Lee (Ulsan National Institute of Science and Technology)
Co-Author(s)
Abstract
Polydiacetylene (PDA) is a stimuli-responsive conjugated polymer whose ene-yne backbone switches on red fluorescence when twisted by heat, mechanical force, pH, or molecular recognition. While its color transition is well studied, how the fluorescence response differs across stimulus pathways has rarely been examined; notably, both thermal and mechanical stimuli amplify PDA fluorescence, yet the two have never been decoupled and orthogonally demonstrated in one material partly because such a comparison requires applying both to identical microstructures. Here we show that thermally and mechanically driven fluorescence amplification can be selectively programmed by molecular design and realized on one organogel platform. We synthesized photocurable diacetylene monoacrylates bearing either freely rotating aliphatic groups or aromatic groups capable of π-π interactions and used maskless lithography to fabricate identical PDA organogel microstructures. Reversible solvent exchange between aprotic and protic solvents delivered a mechanical (contraction) stimulus, while heat was applied independently. The two designs responded orthogonally. π-π interacting organogels amplified fluorescence strongly upon mechanical contraction but negligibly under heat, whereas freely rotating organogels amplified strongly under heat but negligibly upon contraction. Thus, even without strong interactions such as hydrogen bonding, noncovalent π-π interactions can alter backbone twisting, and twisting and fluorescence is governed jointly by the molecular interaction and the type and transmission mode of the stimulus. Combining maskless lithography with molecular design, this study clarifies how molecular interactions and stimulus type govern PDA fluorescence and, for the first time, demonstrates a single platform that converts mechanical and thermal inputs into distinguishable, stimulus-selective optical outputs a multiplexed system reporting heterogeneous stimuli.
