Enhanced fluorescence properties of flexible waterborne polyurethane films by blocking fluorescein isothiocyanate (FITC)

In this study, novel green-emitting waterborne polyurethane (WPU) was synthesized through a blocking prepolymer method to study the effect on fluorescence properties, adopting fluorescein isothiocyanate (FITC) as green-emitting extender was blocked into polyurethane main chain. The chemical structure of fluorescent WPU film was characterized by FTIR and SEM. The effects of the FITC on the fluorescent properties of FWPU were investigated in detail by UV–Vis absorption spectroscopy and molecular fluorescence spectroscopy (MFS), respectively. The results indicated that FWPU has higher fluorescence intensity than FITC and its fluorescence stability is outstanding.