Preparation of PIE‐Active Poly(2,4‐thiazolidinediones) by Oxidative Polymerization and Simultaneous Specific Detection of Cu2+/Co2+ Ions

ABSTRACT In this study, poly( 2, 4 ‐thiazolidinedione) (PTD) is prepared by oxidative polymerization using 2,4 ‐thiazolidinedione (TD) as monomer. PTD exhibits significant polymerization‐induced emission (PIE) at 540 nm, resulting from the intramolecular aggregation of thiazole heterocycles and the formation of electron‐space conjugation. The PIE‐active PTD demonstrates simultaneously specific detection of Cu 2 ⁺/Co 2 ⁺ with detection limits as low as 0.47 µ M and 68.9 nM, respectively, even in the presence of 14 common metal ions and 11 anions. Fluorescence quenching experiments reveal that Cu 2 ⁺/Co 2 ⁺ coordinates with PTD to form a 1:2 non‐fluorescent complex through a static quenching mode. Most importantly, the efficient differentiation between Cu 2 ⁺ and Co 2 ⁺ is achieved using dynamic color recognition technology based on smartphone APP and UV–vis absorption spectroscopy. This approach innovatively combines solution color gradient change with smartphone RGB to establish a semi‐quantitative and convenient detection method. The lower detection limits of Cu 2 ⁺/Co 2 ⁺ reached 36.2 and 37.8 nM m with naked eye recognition, which provides a technological solution for the rapid detection of Cu 2 ⁺/Co 2 ⁺ ions without the aid of large‐scale instruments. In brief, the successful preparation and detection application of PIE‐active PTD open up a straightforward and feasible path for molecular design of fluorescent non‐conjugated polymers from non‐fluorescent monomers.