Polymerization and Depolymerization of Photoluminescent Polyarylene Chalcogenides

Engineering thermoplastics feature high chemical, mechanical, and thermal robustness but often lack advanced functionalities as a result of the harsh conditions required for their synthesis and processing. Herein, we introduce a series of polyarylene chalcogenides (PACs), a classification which encompasses polyphenylene sulfides, polyphenylene oxides, and their derivatives, obtained via the room-temperature polymerization of difluorophthalonitrile and disilyl(thio)ether monomers in the presence of fluoride or amine initiators. The PACs contain thioarene-appended phthalonitriles as the key moiety in the polymer chain, which endows them with the additional properties of photoluminescence and dynamic nucleophilic aromatic substitution (SNAr) chemistry while maintaining the thermal robustness of the parent polymers. The materials display delayed fluorescence, and both the emission wavelength and lifetime were rationally tunable through chalcogen substitution. Dynamic SNAr chemistry was exploited in the demonstration of the selective chemical degradation of the PACs, even as highly crosslinked thermosets, at room temperature. The varied properties of this family of PACs make them interesting to a number of applied fields, including organic light-emitting diodes, chemical sensors, and dynamically responsive materials.