Transition-metal-free click polymerization of aldehyde-activated internal diynes and diphenols toward stimulus-responsive multifunctional poly(formyl ether)s

Among the well-established alkyne-based polymerization methodologies, the polymerization of activated-internal alkynes and phenols remains underdeveloped. Herein, a facile cesium carbonate catalyzed aldehyde-activated phenol-yne click polymerization was reported, and various regioregular poly(formyl ether)s (PFEs) with weight-average molecular weights up to 18 060 g mol−1 were prepared in yields up to 99%. The resultant polymers exhibited multiple stimuli-responsive behavior. The incorporated dynamic acetal moieties enabled the degradation of biomass-based PFEs under acidic conditions. Introducing the tetraphenylethylene (TPE) unit endowed the PFEs with attractive aggregation-induced emission (AIE) properties, enabling the sensitive detection of hydrazine. Thanks to the reaction of aldehydes and diamines, imino-PFEs with significant fluorescence changes according to acid–base variations were obtained and showed potential applications in logic gates, photopatterns and quadruple-mode secure information encoding. Thus, this work not only expands the scope of alkyne-based polymerizations, but also provides a new class of polyethers with versatile functions and applications.