Controlled Self‐Assembly of Polydiacetylene Photoswitches Toward Multi‐Stimuli Responsiveness and Anticounterfeiting Functionality

Abstract

ABSTRACT Achieving precise control over the aggregation and dispersion behavior of photopolymerizable systems in response to external stimuli remains a significant challenge, which has hindered the realization of a single supramolecular platform for programmable multi‐optical outputs. A pyrene–diacetylene optical switching system was rationally designed and constructed by introducing pyrene as a fluorescent functional unit through amidation. The planar aromatic structure promotes ordered monomer packing via synergistic π–π stacking, hydrogen bonding, and hydrophobic interactions, which enhances the preorganization of diacetylene units and establishes a well‐defined spatial configuration favorable for photo‐triggered topochemical polymerization. Notably, the well‐ordered supramolecular arrangement of the Py‐DA monomer enables efficient photosensitization, promoting DA polymerization under long‐wavelength UV light (365 nm) and significantly reducing the reliance on high‐energy UV irradiation. The characteristic excimer emission of pyrene reflects variations in intermolecular distance and packing mode, allowing real‐time visualization of the polymerization process through fluorescence change. The resulting photoinduced polydiacetylene (PDA) exhibits dual‐mode optical responses to both thermal and mechanical stimuli, endowing photopolymerizable supramolecular switches as promising candidates for high‐security dynamic anti‐counterfeiting and temporally sequential multi‐level encryption. This work provides a new design strategy for next‐generation smart supramolecular photonic materials, paving the way for their integration into diverse technological applications.