A novel PET-based copolyester with adjustable fluorescence and degradability

Non-conjugated polyesters have emerged as a promising class of advanced luminescent materials. However, simultaneously achieving broad-color gamut emission, degradability, and robust service performance in polyesters remains a significant challenge. In this study, a poly(terephthalic acid/isophthalic acid-co-glycolic acid-ethylene glycol) (PETIG) ester was synthesized, exhibiting tunable emission wavelengths (λ em ), controllable degradability, high mechanical strength, and excellent thermal stability. By varying the isophthalic acid content, a wide color gamut was achieved. The powder form exhibited a color shift from blue to green, while the concentrated solution showed a transition from green to red, reaching a maximum emission wavelength (λ max ) of 672 nm. Remarkably, the glass transition temperature (T g ) fluctuated by less than 5 % during emission tuning. The polyester demonstrated a maximum tensile strength of 69.8 MPa and a decomposition temperatures (T d,5% ) of 405.2 °C. PETIG showed significantly enhanced degradability compared to PET. Computational simulations revealed that the hydrolysis energy barrier of isophthalic acid is higher than that of terephthalic acid, enabling degradation rate modulation through aromatic ring isomerism. The formation and evolution of ester clusters were found to critically influence both fluorescence emission and degradation behavior. This study leverages the positional isomerism of aromatic units to propose a novel strategy for designing eco-friendly luminescent materials with broad-color gamut emission and multifunctional properties. The resulting materials hold strong potential for applications in high-performance textiles, fluorescent films, and anti-counterfeiting technologies. • A novel luminescent copolyester that achieves a broad-color gamut emission through aromatic ring isomerism. • Based on clusteroluminescence, maximum PL peak of PETIG redshifts from 516 nm to 634 nm. • PETIG simultaneously exhibits enhanced degradability, high mechanical strength, and excellent thermal stability compared to PET. • PETIG has potential applications in high-performance textiles, chemical sensors, and high-value multiple anti-counterfeiting materials.